Urethane Front Bumper Repair

This front "Mach 1 - type" bumper repair write-up got lost in a long thread that went about 4 different directions.

So I thought I'd capture and repost (C9zx) Chuck's repair instructions:

"... . I make no claim to be an expert at body work, or anything else for that matter. What I'm describing is the repair of relatively minor damage (no big chunks missing). The bumper must be sanded to bare urethane, DO NOT USE PAINT STRIPPER OF ANY KIND. I used a DA with 100 grit peel and stick, keep it moving. Do not linger in one spot too long. If you don't have a DA, use a 3M rubber sanding block. If you have long narrow cracks you will need to "Vee" them out (I used a Dremel tool with the miniature cut off wheel). Nicks and gouges need to be free of loose small pieces. Clean everything with wax and grease remover then wipe again with clean dry cloth. The repair material used is an inexpensive alternative to the commercial 3M material and pricey special "gun". It is BONDO Company (now owned by 3M) but it is not bondo. It is PN 280, Bumper Repair Kit. It is flexible 2 part epoxy in a plastic syringe, about $7.00. It is only about an ounce and a half, so only mix what you need at the time. It cures in an hour. Wet sand with 180 or 220 on the block. When you are satisfied that you have repaired all the damage clean everything again and apply the primer. The primer is the key part of this repair. I used Sherwin Williams Spectra Prime with "Ure-flex". When dry, apply a tracer coat. Sand with 320 or 400 on the block. If you find you have missed something that a second coat of primer will not take care of, use more epoxy and repeat process. When satisfied, apply final primer coat. Apply compatible top coat. I used base clear. Final "color sand", compound and polish. I used the 3M series of finishing products. I hope this helps.

Good Luck,

Chuck"

Thanks again to Chuck for this how-to post from quite a few years ago. I fully trust these techniques/steps because the bumper still looks new today!

Here is another similar thread: https://www.7173mustangs.com/thread-urethane-bumper-repair

Ray

Here are a few in-repair process pics:

 

[robnlean]

This is great information. Thanks for digging it out.

 

[AcesArneson]

This front "Mach 1 - type" bumper repair write-up got lost in a long thread that went about 4 different directions.

So I thought I'd capture and repost (C9zx) Chuck's repair instructions:

"... . I make no claim to be an expert at body work, or anything else for that matter. What I'm describing is the repair of relatively minor damage (no big chunks missing). The bumper must be sanded to bare urethane, DO NOT USE PAINT STRIPPER OF ANY KIND. I used a DA with 100 grit peel and stick, keep it moving. Do not linger in one spot too long. If you don't have a DA, use a 3M rubber sanding block. If you have long narrow cracks you will need to "Vee" them out (I used a Dremel tool with the miniature cut off wheel). Nicks and gouges need to be free of loose small pieces. Clean everything with wax and grease remover then wipe again with clean dry cloth. The repair material used is an inexpensive alternative to the commercial 3M material and pricey special "gun". It is BONDO Company (now owned by 3M) but it is not bondo. It is PN 280, Bumper Repair Kit. It is flexible 2 part epoxy in a plastic syringe, about $7.00. It is only about an ounce and a half, so only mix what you need at the time. It cures in an hour. Wet sand with 180 or 220 on the block. When you are satisfied that you have repaired all the damage clean everything again and apply the primer. The primer is the key part of this repair. I used Sherwin Williams Spectra Prime with "Ure-flex". When dry, apply a tracer coat. Sand with 320 or 400 on the block. If you find you have missed something that a second coat of primer will not take care of, use more epoxy and repeat process. When satisfied, apply final primer coat. Apply compatible top coat. I used base clear. Final "color sand", compound and polish. I used the 3M series of finishing products. I hope this helps.

Good Luck,

Chuck"

Thanks again to Chuck for this how-to post from quite a few years ago. I fully trust these techniques/steps because the bumper still looks new today!

Here is another similar thread: https://www.7173mustangs.com/thread-urethane-bumper-repair

Ray

Here are a few in-repair process pics:

View attachment 82661

View attachment 82662

View attachment 82663

 

[AcesArneson]

Thanks guys, I need to do the same. My front bumper is rough!

 

[kcmash]

Can any of you experienced painters tell me how much base coat is needed for a 71 Urethane bumper? I have a partial can, maybe half a pint of base coat. I need to strip my bumper down and refinish. How much is needed to coat a front bumper?

kcmash

 

[Austin Vert]

Can any of you experienced painters tell me how much base coat is needed for a 71 Urethane bumper? I have a partial can, maybe half a pint of base coat. I need to strip my bumper down and refinish. How much is needed to coat a front bumper?

kcmash

Hi kc,

Working out how much base coat needed to refinish your front bar has variations to it.

By that i mean, there are factors which you need to take into account. For example, are you spraying solid color base coat or metallic base coat ?
The covering power of metallic base coats varies depending on the color chosen and/or the brand of paint being used. The poorer the covering power of a base coat color, the more coats are needed to achieve full coverage or proper substrate hide out. (that means no grinning through of any substrate color). Once full coverage has been achieved, then usually two to three light coats are needed to dust out the metallic to achieve an even mottle free metallic appearance.

I am assuming your chosen color will be Grabber Blue. Solid color base coat with a 2k clear coat on top. Solid color base coats usually have better opacity/ hiding power or better coverage to them, requiring less paint used or needed. When you buy paint for your job, it is always wise to buy more than you think you will need for a few reasons. You may have to respray the job due to paint problems occurring. Maybe touch ups in the future. The risk of running out of paint for example.

Anyway, to try and answer your question on quantity to buy, i would say that you will need to end up with a minimum of 2 US liquid pints or 0.9 liters of base coat to do your job and be on the safe side as i have mentioned above. In Australia your quantity would be 2 pints equals 1.2 liters. That said, if you do happen to run out of paint for any reason, it would be a very good idea to have your color made up and formulated, so if you do run out you know you can buy more later and it will be the same color. You tend to get into trouble when a color is eye matched, and you run out on the spray job, and need more, which then, has to be eye matched again. Than can be very tricky to do to achieve an accurate result.

Footnote: Hi Chuck - don't forget the flex aid needed for the solid 2k or clear coats.

Hope that helps,

Greg (pro painter)