Welding Antenna Hole

[Bitsyncmaster]

My new project to justify removing my passenger side fender is to weld up the antenna hole. I'm going to do a lot of practice on junk stainless that I saved from a gas grill. I saved it just for this a long time ago.

I measured the edge of the hood stainless to be 0.031" thick. This junk stainless is 0.035" thick so not only good to practice on but it my be good for the final plug. I think this junk stainless is 304, it is non magnetic.

First problem is how to cut this without distorting the metal. Found IRWIN HHS jig saw blades 36 TPI at the local hardware store. These do work good cutting this thin stainless. There happens to be a 1.5" hole in this junk stainless so now I need to figure out a way to cut a round plug that will fit in that hole.

Has anyone done this? Would like some tips on the whole process.

[Aaron Cake]

Do you have a drill press?

If so, use a carbide hole cutter such as this one:
https://federatedtool.com/mk-morse-cts24-carbide-tipped-hole-cutter-shallow-1-1-2/

The measurement is OD so you will have to find the nearest size with an ID to match your needed 1.5" OD. Remove the center bit (just like you can with a hole saw) to avoid drilling the unnecessary hole.

These are much more precise than a hole saw because they don't have the runout/wobble and cut stainless very smoothly.

How do you intend to weld it?

TIG would be the ideal process.

You would want around 1mm gap between the plug and the fender.

Clamp it with a copper plate below to hold it in place and keep the back side shielded.

Make sure the clamp holds down the plug well because the edges will want to peel up.

Lay your filler in that gap and then quickly pulse the torch while making a circular motion to fuse the filler, patch and fender.

Be as quick as possible with the weld.

Alternate side to side making these small welds, allowing it to cool between welds.

Keep the material from overheating.

Once done, use a fine grinding tool like a disk on a Dremel to slowly take down the welds. Don't introduce heat.

Once you have the welds just above the surface of the fender, switch to a file and finish out the rest by hand.

Then proceed with the standard blending and re-graining well documented.

Welding stainless is a right bitch so practice a lot on the spare panels. You will find that the biggest challenge is warpage.

[Bitsyncmaster]

Do you have a drill press?

Thanks for that great info. Yes I have a drill press and a TIG welder. I new to TIG welding so have to do a lot of practice on thin metal.

[Bitsyncmaster]

After watching a bunch of car guys welding videos, I made a few spot welds on some junk stainless sheet. It did result in a little warping. I then hammered those spot welds and it did take out the warp. What the video said was the weld contracts as it cools. He showed it closed the gap he had made. Then after hammering those spot welds that gap widened. They can't use heat sink backing working on the car repairing a fender.

Now it's not going to be as easy doing that on the fender. Probably will need to make a tool like Chris uses to removed dents in the stainless.

I still need a lot of practice TIG welding.

[Helirich]

I have done a lot of SS welding, but I don?t claim to be an expert. You definitely want a backing or the back side will need to be bathed in argon. You can not weld thin stainless without something behind. (Unless it?s inert gas)

To be honest, I wouldn?t try this unless I already decided I will buy a new fender.

[Bitsyncmaster]

I have done a lot of SS welding, but I don?t claim to be an expert. You definitely want a backing or the back side will need to be bathed in argon. You can not weld thin stainless without something behind. (Unless it?s inert gas)

To be honest, I wouldn?t try this unless I already decided I will buy a new fender.

Of course you will need a block to clamp the plug in place. I will probably cut one with aluminum but I do have some copper sheet. I even have a block of copper. Once it is cut you can keep using it.

[Bitsyncmaster]

If I chicken out, I can machine a plug from 304 stainless on my lathe which will look better than what is there now. But more practice will decide what I do. I have am OEM stripe I would like to keep.

[glockworks21]

If I chicken out, I can machine a plug from 304 stainless on my lathe which will look better than what is there now. But more practice will decide what I do. I have am OEM stripe I would like to keep.


ive been drinking for a few hours so take this with a grain, but maybe just cap it? seems like a lot of risk...

[Patrick C]

If I chicken out, I can machine a plug from 304 stainless on my lathe which will look better than what is there now. But more practice will decide what I do. I have am OEM stripe I would like to keep.

Worst case scenario, you are buying a $375 RFF on the last day of DMCH's big sale on January 31st when everything is back on sale again.

[JohnZ]

Hi there Dave! Interesting project you have got there, as usual!

I did not push myself into welding, but I had the antenna hole too, and the thing was all broken and ugly! So what me and my friend did was to plug it with a piece of steel and wood, and then regrain it...and the result was awesome! I honestly don't remember exactly how we did it, it was a long time ago, but here are a couple of pictures where you can see the final result!

71968. 71969

It's not a close up, but you can zoom in! I saw that they actually sell a plug like that nowadays!

:)

[r00b]

Sounds like it's worth a try, if it doesn't come out, he could always drill it out again and try again or add a plug.

[Bitsyncmaster]

Sounds like it's worth a try, if it doesn't come out, he could always drill it out again and try again or add a plug.

I'm still practicing my TIG. The problem is failure would probably warp the fender. Otherwise your correct, just plug it. I think I need to practice on some thicker stock at feeding the filler rod. I have no problem on thin stainless just butt welding it without filler.

[DMC-Ron]

Dave,
You might consider reaching out to Chris Nicholson or some other DeLorean regraining expert to see if they have ever filled in an antenna hole and how they might have done it.
Ron

[Aaron Cake]

Thanks for that great info. Yes I have a drill press and a TIG welder. I new to TIG welding so have to do a lot of practice on thin metal.

You definitely want to back it up with some material. Copper is the most ideal as it will pull heat aggressively away from the stainless. Plus, the backing seals the rear of the weld so you won't get sugaring/oxide formation from air being drawn into the weld.

I was thinking about this last night and you're going to want to brace the fender as much as possible. I suspect the weld will pull the mounting flange up due to the lack of material in that area. On the other side, the face of the fender, the amount of material will probably limit the pull.

The vendors probably have a jig for this to keep the fender aligned.

I've done a lot of stainless welding primarily on manifolds and tubing. Stainless loves to warp. In fact, even a 3/4" plate with two manifold runners welded to one face will be curled 1/8" at each end. Learned this lesson the first manifold I made 20+ years ago:

71972

Look how much the edges have pulled up.

All subsequent manifolds were thoroughly clamped down to a 1" plate (which also served to seal the runners for back purging) prior to welding but 1 - 2MM of warp still happens.

Since you have a lathe, I'd almost be tempted to turn a plug with a flange on the bottom (think top hat shaped) that stands a bit proud of the hole. That will give more material to work with, stabilize it a bit, and allow you to grind down to the level of the fender instead of trying to keep the top level.

[Bitsyncmaster]

Since you have a lathe, I'd almost be tempted to turn a plug with a flange on the bottom (think top hat shaped) that stands a bit proud of the hole. That will give more material to work with, stabilize it a bit, and allow you to grind down to the level of the fender instead of trying to keep the top level.

Now that is a great idea I never thought of.

I did try your method of laying the filler rod on the joint and then starting the arc on the filler. The rod melts instantly so keeping the heat on to melt the joint and then you can pull the rod off. It does seem to work consistently laying down a good spot weld.

[Bitsyncmaster]

It looks like to pull the fender is going to be a big effort. I pulled the top bolts under the top hood seal. One had four washers and the others 2 or 3. I pulled the 4 Philips screws under the door seal. Looks like I need to pull the rocker panel to get some bottom screws. Now the front screws look like they are going to need the front fascia removed.

[Timeless]

It looks like to pull the fender is going to be a big effort. I pulled the top bolts under the top hood seal. One had four washers and the others 2 or 3. I pulled the 4 Philips screws under the door seal. Looks like I need to pull the rocker panel to get some bottom screws. Now the front screws look like they are going to need the front fascia removed.
Yes the fascia will have to come off. A R&R task I don't think anyone enjoys doing.

[Bitsyncmaster]

Those rocker screws won't move. Are they in metal clips. Looks like they will need to be drilled out.

Edit:
Looks like they are riv-nuts. Dang. There are so many.

[glockworks21]

there is a good video done by alex from legit street cars of him removing the front facia. maybe worth a watch just to see whats in there
i think he said it took 6 to 8 hours.. i can send link if you want..

[Bitsyncmaster]

there is a good video done by alex from legit street cars of him removing the front facia. maybe worth a watch just to see whats in there
i think he said it took 6 to 8 hours.. i can send link if you want..

Thanks. Yes send me the link. This is turning out to be more then I bargained for.

[glockworks21]

Thanks. Yes send me the link. This is turning out to be more then I bargained for.

https://youtu.be/yAjjPyL5Fvs?si=Ux5rjAMTfFV8meh3


starts at about 15min mark

[Bitsyncmaster]

Got that rocker off. What a PIA to drill the heads of those screws. Looks like I will need new blind nut locations. There seems to be foam backing the original blind nut so I can't just drill the end and push them in.

[Bitsyncmaster]

I was able to get some long nose vise grips on the bracket for the antenna and able to remove it just removing what I've done so far. I do see the two bolts for the door pin fixture. That is one of the main reasons I wanted to pull the fender. I plan to move it up. Now on to pulling the front fascia so I can pull the fender.

Antenna hole is 1 inch diameter. Not a very clean cut hole. Needs a little hammer work also.

[JETS 81 DMC]

Worse case scenario from the plumbing world. Something like this or similar

Stainless Steel Sink Plug Anti-leakage Silver Faucet Hole Cover

https://www.aliexpress.us/item/3256810007537894.html?src=google&pdp_npi=4%40dis%21USD%210.70%210.51%21%21%21%21%21 %40%2112000051478726394%21ppc%21%21%21&src=google&albch=shopping&acnt=708-803-3821&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&gclsrc=aw.ds&albagn=888888&ds_e_adid=&ds_e_matchtype=&ds_e_device=c&ds_e_network=x&ds_e_product_group_id=&ds_e_product_id=en3256810007537894&ds_e_product_merchant_id=554362142&ds_e_product_country=US&ds_e_product_language=en&ds_e_product_channel=online&ds_e_product_store_id=&ds_url_v=2&albcp=19678427463&albag=&isSmbAutoCall=false&needSmbHouyi=false&gad_source=1&gad_campaignid=19686402437&gbraid=0AAAAAD6I-hEJ7mLJ7pS5-o5llvwtIiezq&gclid=CjwKCAiAybfLBhAjEiwAI0mBBhYjdyx9zm4JmQHuc31_ 8ipfJ04ljQpcjEQxO3nJZIXyNbYRGl0gwhoCsUIQAvD_BwE&gatewayAdapt=glo2usa

[Bitsyncmaster]

I was able to remove those Philips screws on top without removing the hood. Just setting a short hex bit in the screw, holding it down with a file and using and open end wrench. Once you back them out a turn you can just use your fingers to finish.

We are going to get real cold in a few days so work will probably stop until it warms back up. My garage heat pump just ices up a lot. May just need a charge but it's R12.

[r00b]

I was able to remove those Philips screws on top without removing the hood. Just setting a short hex bit in the screw, holding it down with a file and using and open end wrench. Once you back them out a turn you can just use your fingers to finish.

We are going to get real cold in a few days so work will probably stop until it warms back up. My garage heat pump just ices up a lot. May just need a charge but it's R12.

How large is your garage, a diesel heater might work well for heating at a low cost.

[todd1561]

It can definitely be done, I remember stumbling across this page ages ago, was able to find it again somehow. I don?t recall what the affiliation was between the stateside Grady and Europe. They do mention the type of welding rod used and some other details that may be useful.

https://www.pjgrady.co.uk/aerial-hole-repair

[Aaron Cake]

316 is an interesting filler choice. Normally when welding stainless, one goes "one grade" up so typically 304 is welded with 308/308L filler.

316 is tougher to weld because it is easier to burn out the chrome and moly. Generally a 316L rod is used for welding because it contains more of this, and less carbon.

316 also tends to pull more.

Not saying that Grady is wrong (they've welded more DeLorean fenders than I've touched, probably), just that 316 is an interesting choice.

[Bitsyncmaster]

Got the fender off. Did not have to pull the whole fascia off, just pulled that end till I could get at the fender screws. I did break the two screw/nuts on the top spoiler that squeeze the fascia to the bracket. The two spoiler nuts holding the fender did come off. So if your just removing the fender you don't need to remove the headlights and turn signal. Just have to remove the side light. Also the rock screen can stay, just remove the top bolts. You do have to flex the fascia to get that alignment bolt on the side out.

Here is a photo of the door pin bracket. Have not decided yet if I will just modify the floating nut of move the bracket up to get my door pin higher.

Have not got my 304 stainless round rod yet. I've been thinking I should practice welding one of my "stepped" plugs into my scrap sheet first. It may need me to keep more heat on the plug since it will be thicker than the fender sheet metal.

[Bitsyncmaster]

Looks like I can move the bracket up a little (about 0.20"). That is about what I need for up but I want to have a little more adjustment both up and out. So I will cut the floating nut to get more. You can't really shim the bracket out. It mounts hard to the tub joining bracket.

The floating nut has the hole offset a little. Maybe I can drill and tap another hole rather then cut the nut down. Another option is I make a new floating nut from 4130 steel with the tapped hole offset more.

[Bitsyncmaster]

Here is the floating nut. It's 0.312" thick. It is square, the photo make it look not. I ordered an M12 - 1.0 tap and will try to offset a new hole.

[Bitsyncmaster]

I should have put these last posts in my door hard to close thread. Anyway, I drilled a center hole 0.200" more offset then the original hole. Waiting on my 11 mm drill bit and the 12 mm 1.0 tap.

[Bitsyncmaster]

The cold weather has put a damper on this. But I did think of a better way to make the stepped 304 plug. Just cut it from 0.060" sheet and then cut the step in my lathe. The fender is 0.027" thick. It would be thinner at any bends. I don't want the plug to be to thick or welding to the thinner fender may be harder to do.

[Aaron Cake]

The nice thing about it being a bit thick is that it functions as a heat sink. You can start the weld on the thick side and roll it quickly to the thin side.

[Helirich]

The nice thing about it being a bit thick is that it functions as a heat sink. You can start the weld on the thick side and roll it quickly to the thin side.

This.

[Bitsyncmaster]

I tried to cut that step in the plug on the lathe and it does not work. The problem is the 0.062 stock is flexing because it's not sitting flat on a solid surface. It's mounted on a four jaw chuck but that only supports flat about 0.35" at those four locations. What happens is the cutting bit bites into the stock.

I may try putting the chuck on my rotary table and see if using an end mill on my milling machine will do the job.

Last resort will be cutting it from solid round stock.

[Helirich]

You could put a washer behind it on the lathe. But I think the round stock is the answer. Then you don?t have a hole to weld up. I?m assuming you have the .062? on a spindle.

[Bitsyncmaster]

You could put a washer behind it on the lathe. But I think the round stock is the answer. Then you don?t have a hole to weld up. I?m assuming you have the .062? on a spindle.

I tried the end mill and that did not work. I did think of clamping two plugs together but decided to just go with the round bar stock. The only problem with the bar stock is cutting it when I've finished the step. Someday I need to get one of those bandsaw cutoff machines.

[Bitsyncmaster]

Here is my test plug to weld into my scrape stainless sheet just to see if I can do it. My scrape sheet is 0.037" thick so I machined the step to 0.042" to give me an extra 5 thousands above the hole. I plan to try welding it today.

If it works out, I thought of anther way to try machining the plug. I will cut two 2.00" disks from my 0.062 sheet and weld them together at the edge. That may let me machine the step. Then I can cut to get one disk 1.4" diameter.

The fender is thinner at 0.028" thick.

[Bitsyncmaster]

I tried to weld it to my scrap. What you really need is a custom built clamp to hold the "fender" down on the plug all around the hole. It lifted because the clamp was not close to the weld. I guess you could clamp one spot, weld a spot and then move the clamp to do another spot.

It really takes a lot of heat on the thicker stepped plug. It did work on one spot. Seemed like 10 seconds to get that plug to puddle. My TIG is set for 30 amps which worked with same thickness joints.

I think I'm going to machine a stainless plug that bolts on.

[Helirich]

I tried the end mill and that did not work. I did think of clamping two plugs together but decided to just go with the round bar stock. The only problem with the bar stock is cutting it when I've finished the step. Someday I need to get one of those bandsaw cutoff machines.

Do you not have a parting tool for your lathe?

[Bitsyncmaster]

Do you not have a parting tool for your lathe?

Never had much luck with them. My lathe is a small hobby unit. What I do is hack saw it while the part is rotating. Not to bad with aluminum but that 304 takes a long time.

[Bitsyncmaster]

Here is the finished plug. I even put a grain on it with 80 grit sandpaper. I was just thinking of gluing it in but sitting it on the fender, the front side looks flat but the back side of the fender has a little curve or bump So I'm going to machine a cup to screw it in with some force. Maybe that will make it sit flush all around.

I made the top 1.400" dia. to hide the mess that the antenna "bite" bars made. The one inch inside was made 0.400" long so I could tap for a 10-32 stud. I will loctite that stud and use a nut to clamp it in the fender.

[Aaron Cake]

Do you have current control on the TIG? A foot pedal or torch control? You really need to be able to pulse a higher current to get the puddle formed on and then lower the current to draw the puddle to the thinner section. 10 seconds is a very long time. If your TIG has pulse, even better. Makes it very easy to weld stainless.

[Bitsyncmaster]

Do you have current control on the TIG? A foot pedal or torch control? You really need to be able to pulse a higher current to get the puddle formed on and then lower the current to draw the puddle to the thinner section. 10 seconds is a very long time. If your TIG has pulse, even better. Makes it very easy to weld stainless.

I do have a foot pedal but if I use it, that just adds another function that I need to practice with.

[Bitsyncmaster]

Finished the cup for my antenna plug. Made will aluminum. All this was way more work than I thought it would be. I will fit it onto the fender tomorrow.

[Helirich]

I do have a foot pedal but if I use it, that just adds another function that I need to practice with.

I think it?s appsolutly mandatory to use a current control with tig. When I learned in high school, they didn?t have any and yes, it was possible, but I can?t even conceive of it now.

[Bitsyncmaster]

If it wasn't for the side stripe I wanted to keep, I would just recommend you buy an NOS fender without the antenna hole. The hole plug did pull the fender and plug tight with my "cup" clamping it with the nut. Anyway, fender is mounted and door pin adjusted. It must have been the doors were a little off when they put the stripe and rub strips on. If you look at the bending alignment the door is still a little low. Same on the drivers side.

I now have to install new riv-nuts to mount the rocker. Also need to glue the rubber seals back on.

Then move onto doing the same door pin change to the drivers side.