Installing Stainless Bumper Letters - Adhesive?

[jawn101]

So way, way back when (like, in 2012) I ordered a set of stainless letters for my rear bumper from http://www.deloreaneurotec.uk/viewtopic.php?f=102&t=430&sid=d274d8c0a34dab4d7ead9b0b3dba255d

They sat in my parts box for what's now 5 years. I wasn't sure I was going to keep my rear bumper forever, and wanted to get the black parts at least buffed up to looking nice before I went and stuck these in. Now I realize how silly waiting was, and another owner here got my black urethane looking like new in all of 5 minutes, so I'm finally ready to "take the plunge" with these letters. Man, do I sound lame.

Anyway, the letters sold at the link above are not self-adhesive. I don't know how I should attach them to the bumper - I bought some 3M mounting tape but they are already the exact thickness of the embossing in the bumper - if I put a layer of tape under there too, they will stand proud and I don't want that.

Should I glue them in? What is the best adhesive? Is there any downside to gluing, other than being generally irreversible?

I'm not sure if the tape would really be reversible either, given that you'd have to pry them up under the best of circumstances and that could damage the bumper even if the adhesive was weakened with a heat gun first.

[Bitsyncmaster]

I would think a thin double sided tape would hold the best. With the heating in the sun and the different expanstion rates a hard glue probably would not hold.

Now maybe a rubber contact cement would work. That is the type you brush on both surfaces, let dry and then attach together. They sell it in a bottle with a brush made into the cap called DAP Weldwood.

[jawn101]

I thought the same thing about the 3M foam tape, that it would counteract the expansion rates. But the thinnest one I could find still made the letters stand out past the bumper. Do you know of something thinner that would be suitable?

Not a tremendous fan of the glue idea, really - just thought it might be the only option. I saw the Weldwood stuff on the same shelf at Lowe's as the 3M tape I got, but glanced past it because I assumed it was wood glue.

[jawn101]

I actually just found this on Amazon: 3mm x 25M Clear Double Sided Strong Adhesive Acrylic Tape For Mobile Phone Laptop Tablets LCD Screen https://www.amazon.com/dp/B019OQ4ZG0/ref=cm_sw_r_cp_tai_cYJbzbHZYH5BR - says that it's 0.18mm thick, VHB, high temperature. Given that it doesn't need to support much weight at all, this might just do the trick.

[iflights]

I actually just found this on Amazon: 3mm x 25M Clear Double Sided Strong Adhesive Acrylic Tape For Mobile Phone Laptop Tablets LCD Screen https://www.amazon.com/dp/B019OQ4ZG0/ref=cm_sw_r_cp_tai_cYJbzbHZYH5BR - says that it's 0.18mm thick, VHB, high temperature. Given that it doesn't need to support much weight at all, this might just do the trick.

VHB is a trademark of 3M, but I don't see 3M listed in the description anywhere. I'd be a little cautious as you may not be getting what you are expecting in terms of durability and overall performance.

If you use VHB tape you might also consider the 3M 94 Primer which does an outstanding job of preparing surfaces for tape adhesion.

[jawn101]

Thanks for the tip. I usually only trust (or give strong preference to) 3M products but I did realize this isn't theirs. I'm more concerned with thickness, or in this case thinness for this application. The letters are quite light so it should be pretty reasonable. For $6 it's worth a try I think.

[DMC-81]

Hi Jon,

I used clear RTV silicone sealant and sanded the back side of the letters when I did mine..

Before..
51221

After...
51222

I think I got my letters from the same place.

[jawn101]

That's beautiful. I'm after the same effect, of course. Just not thrilled with the idea of glue for some reason! I ordered the tape I linked above and will give it a shot, if it sucks or can't hack it, I will go with a very light bead of silicone as you did. Lord knows I have enough of that laying around, in a half dozen colors. Seems like these cars are basically made of it.

[DMC5180]

How Thick are the letters?


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[David T]

Clear 3M trim adhesive used sparingly. Clean both surfaces well with alcohol first.

[mluder]

You should be able to find double sided trim mounting tape at any auto parts store. They should have something thin enough for this application.

Cheers
Steven

[DMC1890]

I have used a product from my local auto supply store called 'emblem cement' that seems to be made for this purpose.

[Nicholas R]

I've got stainless bumper letter in 3 places on my car. 1 set in the rear bumper, 1 set in each ground effects skirt on the left and right side of the car. I've always used 3M 2 sided tape trimmed to the shape of the letter. Mine always came pre-tape backed, but I did remove my bumper letters once to repaint it. For that I removed the tape residue, then added new tape. Apply fully to the back of the letter, then trim the excess with a razor/exacto knife.

[Mario]

I actually just found this on Amazon: 3mm x 25M Clear Double Sided Strong Adhesive Acrylic Tape For Mobile Phone Laptop Tablets LCD Screen https://www.amazon.com/dp/B019OQ4ZG0/ref=cm_sw_r_cp_tai_cYJbzbHZYH5BR - says that it's 0.18mm thick, VHB, high temperature. Given that it doesn't need to support much weight at all, this might just do the trick.

I have used that adhesive before, it's good stuff. Should work fine. I also like to use 3M's 468MP adhesive, it's pretty much the same thing:
https://www.amazon.com/gp/product/B007Y7CZ32/

Just make sure you clean both surfaces with rubbing alcohol first, and it will stick very well. If necessary, you can still take it off in the future, though it will be difficult to peel the letters off without bending them.

[jawn101]

Thanks everyone for the tips! I'm committed to the 3M tape that I ordered now, so I will give it a try and see what happens. The one that Mario posted looks like exactly what I would have been looking for, but it didn't come up in my searches.

[lazabby]

...Now I realize how silly waiting was, and another owner here got my black urethane looking like new in all of 5 minutes...

What did the other owner use to get the black urethane to look new?

[jawn101]

What did the other owner use to get the black urethane to look new?

Just a good rubdown with that 303 Aerospace protectant stuff. Which I have a ton of in my garage and never even tried. Feeling kinda dumb :)

[jawn101]

I have used that adhesive before, it's good stuff. Should work fine. I also like to use 3M's 468MP adhesive, it's pretty much the same thing:
https://www.amazon.com/gp/product/B007Y7CZ32/

Just make sure you clean both surfaces with rubbing alcohol first, and it will stick very well. If necessary, you can still take it off in the future, though it will be difficult to peel the letters off without bending them.

So I was able to cancel the tape I ordered and got this 3M 468 instead - but it doesn't stick at all to the bumper!! I prepped it twice with alcohol and still nothing. No bond at all. Sticks to the stainless letters well enough but not one jot to the bumper.

Sooo... any other suggestions? :)

[DMC5180]

Did you peel film from both sides?


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[jawn101]

Did you peel film from both sides?


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Lol... I'll try not to take that personally. But yes :)

[DMC5180]

We use that same product at my work and it sticks to painted surfaces very well.

Alcohol prep and an adhesion promoter called primer 94 (3M) commercial use only.

It is VHB adhesive without the foam layer. When I installed letters on my car 20 plus years ago, the VHB tape on them was definitely thicker than 5 mil. How thick are your letters? Mine were .032 thick.


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[jawn101]

We use that same product at my work and it sticks to painted surfaces very well.

Alcohol prep and an adhesion promoter called primer 94 (3M) commercial use only.

It is VHB adhesive without the foam layer. When I installed letters on my car 20 plus years ago, the VHB tape on them was definitely thicker than 5 mil. How thick are your letters? Mine were .032 thick.


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My bumper is still unpainted, raw urethane.

These letters are 0.053", 1.34mm thick.

[DMC5180]

My bumper is still unpainted, raw urethane.

These letters are 0.053", 1.34mm thick.

Have you ever applied any silicone based blackening treatment to the bumper?


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[jawn101]

Have you ever applied any silicone based blackening treatment to the bumper?


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The only thing ever applied to it was that 303 Aerospace Protectant which I do not think is silicone based. But this may indeed be the root of the problem...

"303® Aerospace Protectant™ is a water-based proprietary formula that contains no petroleum distillates, alcohol, mineral oil or harmful silicone oils."

[jawn101]

I've read on some other forums that WD-40 can help remove this product. Anyone know if that would be harmful to the bumper? When Chris Nicholson regrained my car a few months ago I got it back basically soaked in the stuff, so it can't be all bad...

[DMC5180]

The only thing ever applied to it was that 303 Aerospace Protectant which I do not think is silicone based. But this may indeed be the root of the problem...

"303[emoji768] Aerospace Protectant[emoji769] is a water-based proprietary formula that contains no petroleum distillates, alcohol, mineral oil or harmful silicone oils."

It's got something in it otherwise they could not call it a protectant. It would be water.

You might try some regular VHB like a command strip. Stick it on an open flat space of the black area just too how it sticks. This way you can easily pull it back off with the tab once you see how it performs.


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[jawn101]

It's got something in it otherwise they could not call it a protectant. It would be water.

You might try some regular VHB like a command strip. Stick it on an open flat space of the black area just too how it sticks. This way you can easily pull it back off with the tab once you see how it performs.


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Agreed it has to contain some kind of protectant, just not sure what it's based on. I will try something more gentle to remove it, like some regular old Dawn dish soap. I can always re-treat the area after I have it cleaned off and the letters glued in.

[DMC5180]

That's worth a shot. Otherwise wax and grease remover is pretty much the norm for most prep cleaning.

Did you look up the SDS sheet for the tape? It has instructions for application for best results.We find we have the most success using an adhesion promotor in our application, since It has to withstand airflow in access of 230 mph. (Aircraft wing)




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[jawn101]

That's worth a shot. Otherwise wax and grease remover is pretty much the norm for most prep cleaning.

Did you look up the SDS sheet for the tape? It has instructions for application for best results.We find we have the most success using an adhesion promotor in our application, since It has to withstand airflow in access of 230 mph. (Aircraft wing)




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Where can I get the adhesion promoter? You've mentioned it a few times but keep saying it's commercial only.

Edit: holy hell, I looked it up and it only comes in pint size cans for like $60.

Any idea if something like this would work instead? https://www.amazon.com/3M-Adhesion-Promoter-Sponge-Applicator/dp/B018WQ2T3O/ref=pd_lpo_vtph_328_bs_t_2?_encoding=UTF8&psc=1&refRID=ZFAY1MFTGGZH7AVDZFG4 - It's not the "primer 94" but is a 3M adhesion promoter and comes in single use sponges that would be more suitable for this type/amount of work.

[DMC5180]

That looks like a great alternative. It would not surprise me that it is Primer 94. Just a different PN for consumer sales. Primer 94 has highly toxic fumes. You must where a respirator when using it.

I noticed the application instructions are very specific in order to minimize the amount of exposure.

Protective gloves is a must.


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[jawn101]

That looks like a great alternative. It would not surprise me that it is Primer 94. Just a different PN for consumer sales. Primer 94 has highly toxic fumes. You must where a respirator when using it.

I noticed the application instructions are very specific in order to minimize the amount of exposure.

Protective gloves is a must.


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Great, thanks. Now just to find something to safely get that 303 off the bumper. On my tour of o'reilly today most of the strippers/degreasers/surface prep chemicals had warnings scary enough to not bring it anywhere near my car.

[DMC5180]

Wax and grease remover or Prep-sol is mostly mineral spirits. Most companies create blends of common hardware store chemicals. Just don't use anything with MEK or ACETONE. It will attack the urethane.


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[eight8toy]

Save yourself the hassle and just order the $20 letter set off eBay. It came with the 3M prep stuff and each letter was taped and ready to stick on. Was a very simple process and still looks great on mine.

[jawn101]

Save yourself the hassle and just order the $20 letter set off eBay. It came with the 3M prep stuff and each letter was taped and ready to stick on. Was a very simple process and still looks great on mine.

Hmm, got a link? Wish I'd known about that before, lol. Are they stainless or Mylar? $20 seems awfully cheap for stainless.

[jawn101]

Wax and grease remover or Prep-sol is mostly mineral spirits. Most companies create blends of common hardware store chemicals. Just don't use anything with MEK or ACETONE. It will attack the urethane.


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I'm trying some uncut dish liquid for the moment, just rubbed it in and will let it sit for 10 min or so, then go wipe it off. See if that does anything to help.

[eight8toy]

I'm at work and can't access Ebay but if you search for "Delorean letter set" it should pop up for like $19.95. They are not stainless steel so ya that's why they are so cheap. But they have a nice mirror finish and took about 5 minutes to install!

[jawn101]

I'm at work and can't access Ebay but if you search for "Delorean letter set" it should pop up for like $19.95. They are not stainless steel so ya that's why they are so cheap. But they have a nice mirror finish and took about 5 minutes to install!

Ah, yeah - I found those. I prefer the actual metal ones, they are made from 304 and match the body of the car - plus I already spent a pretty good chunk on them :) Thanks for the tip though. Can't argue that this is an annoying process.

[DMC5180]

Where did you get your letters? I didn't know anyone sold them without adhesive backing tape.


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[jawn101]

Where did you get your letters? I didn't know anyone sold them without adhesive backing tape.


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Yeah I guess I found the only supplier. And I didn't know they weren't backed when I bought them, I just sorta assumed they would be. I linked it in my first post, but it was the EU club: http://www.deloreaneurotec.uk/viewtopic.php?f=102&t=430&sid=d274d8c0a34dab4d7ead9b0b3dba255d

[jawn101]

So after a few applications of dishsoap and good scrubdowns, I tried sticking a loose piece of that 468 tape to the bumper. It stuck quite well. I removed it before it got too comfortable, but I'm now confident with the proper prep as you've outlined that it will stick beautifully. Will report back when I know more.

[jawn101]

Dennis - your inbox is full, but here's my message anyway :)

Thanks man. Sorry to be a pain. I think foam tape is really what's called for here rather than the transfer adhesive I've been using, since the bumper is ever so slightly contoured and it really needs that buffer to make it stick well. But these letters are so much thicker than the ones you said you have, there's just no tolerance for the grey trim tape I'd normally use for such a thing.

Will give the glue a try this weekend I guess. [emoji3]

[DMC5180]

I think you just hit on it. That slight contour is preventing full contact of the thin adhesive layer because the letters are too stiff. Do the letters fit within the recessed area with a slight gap or do they sit on the raised radius?

https://uploads.tapatalk-cdn.com/20170506/28d3d5244fdc1d8b4a2f60e7751a2bda.jpg

Mine came from D1 back in 94. My one and only order from them before getting D-listed by Ed [emoji6]


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[jawn101]

They sit fully within the recessed area. Ah, D1.

[Mario]

Man, sorry to hear the 468 let you down! I forgot that the bumper was curved slightly there.

[jawn101]

Man, sorry to hear the 468 let you down! I forgot that the bumper was curved slightly there.

Yeah, the slight variances in height were the downfall there.

I ended up finding some very, very thin grey 3M trim tape at O'Reilly - I trust that stuff, always have. Here's the result:

http://dmctalk.org/attachment.php?attachmentid=51375&d=1494275179

http://dmctalk.org/attachment.php?attachmentid=51376&d=1494275215

Very pleased at the end of the day :)