KBD85

So, ive seen alot of questions on how to fix our plastic bumpers and plastic parts. I was in the autobody business for about 10 years prior to my current occupation. So, some of you have seen my bumper grafting thread, and i took a lot of pics of the process, so some of these pics may be familiar. I took out some of the more detailed ones to show the mending process. I will explain what i did as i post the pics, there are going to be alot!! but i think it explains the process better than words.

So, lets begin. this works very well, and i have done it for years and years now. The trick is all in the process. If you dont prep right it will not work!

So, here is where i need to shorten my air dam, so im cutting out the space i need and am going to mend it back together.

KBD85

This is cutting it apart. Here I just used a cut off wheel on my electric grinder. You can use what ever you want, but the seems need to be rough (sanded) so cutting it with sissors is ok, but creates a slippery edge, you will want to sand that with very agressive sand paper, 24 grit is ideal. Sometimes I use 36 grit.

KBD85

More pics of it being cut appart. Also here ive started sanding up the surface to be bonded. I screw it to a wood board so I can get a good sanding without it flying all over the place. Just screw it down with some grabber screws.

KBD85

Alright. now we are cleaning up the parts i cut out. I am going to use them as a backer. Now this is very important if you have the space. It will make for a very strong bond. Sand all surfaces to be glued together with very agressivev grit.

KBD85

Now I am lining up the front part to the back part. This is without the backer, just the front and back lined up to where i want them. the next post will be of the backer pieces.

KBD85

Alright. Its all lined up. Here all parts are sanded and ready to be bonded together. I like to screw the part if possible, to a wood base with short grabber screws. Dont worry about all the holes. These will help with bonding anyway. The bonder i am using is a panel bond from 3M. You use a two part epoxy gun to apply the epoxy. You also can pump it out on a surface without the mixing tip on if you want to mix it with a bondo spreader and apply it that way.

KBD85

This is just the parts bonded together. Also a look at what the epoxy looks like without the mixig tip on. I like to spread it like bondo to smooth it out.

KBD85

In the previous post you can see how I bonded the sides to the nose cone. See the screws holding it all together. You realy want to mash these part together tight with screws or clamps or some way that you can leave it for cure time. I like to wait a day. It will be very hard when it is cured.

Here we are switching to a different area. It shows some different ways you can use this process. As you can tell this is quite extreem, but you can see how you can repair a simple tear if needed.

O.K. a little catch here that i think i should put in. The gun used for this product is kind of expensive. You can get it at a shop for body supplies, but it does cost a bit for the guy who may only use it once. could be a show stopper. maybe if your lucky they may rent it for a few bucks.

KBD85

Now we have it all bonded, we have the shape we want. Now you want to grind a rough surface and smooth out the epoxy. Make sure there are no shiny spots. It all needs to be sanded down. we are getting ready for a finnishing cream for flexible bumpers. I used a product from valvoline, part number 8003 called plio grip.

KBD85

We now have it roughed in, and put down the first layer of my finishing cream. You want to repeat this process untill the surface is to your satifaction. All low spots filled in. Ignore the color difference. the first spread was some old 3M stuff i had laying around and finished it off.

KBD85

Now im to the point of basic body work. You want to make sure you are using products for flexible surfaces. right to the clear coat. Base color is just normal. Your primer you want to use a nice high quality flexible filler. The clear coat i put a flex agent in it.

KBD85

Alright. I just threw this together. I hope this helps some people. There were alot of questions on this matter that inspired me to help out. This site has helped me in so many ways, so I need to do my part and put what I know out there to help others. thanks so much TGO!!!!

TIMMYS89GTA

iTrader: (28)

Nice Ken! Good write up!(:

thatoneguy5x

I've read your other thread before! amazing work its always hard doing something for the first time but this definitely helps. I always try to get things pretty from the very beginning but I guess there are steps in between! who knew....

84 1LE

iTrader: (9)

Thats an interesting mixture of parts.Very nice blend, it looks like it was made that way.Great work.
What made you decide to use the 82-84z section?
What did you use for a impact absorber?
What went into the signal light pockets?

KBD85

-the 82-84Z section was just cuz i had it laying around. I actualy didnt think this was going to look good at first. So i used a broken up Z cover and a TA cover with issues. It just happen to turn out realy cool. So it was just more of a curiosity of how it would look, experiment.
-my impact absorber is off. the large opening of the Z cover just happens to lay dead square against the impact bar. and i have angle edges screwed under where the camaro turn signal light holes rest. so it totaly supports itself like it would with the egg crate shape holder.
-the turn signal pockets for now are going to be the fifth gen camaro square headlights. they fit perfectly. If i was rich, a twin turbo system would ue those holes

I dont know if you have read the front bumper thread I did, but it shows this project more clearly as a project. This was just to try to show how to mend this stuff if one wanted to do that. You can go here to see the whole front bumper grafting. https://www.thirdgen.org/forums/body...-grafting.html

KMdoza7

iTrader: (1)

Good write up. this will be very useful when i fix my bumper thanks

Base91

iTrader: (1)

You name a valvoline product as a flexible filler. Would you list some of the other stuff? Paint etc. that can be used on a flexible bumper cover.

82tarecaro

iTrader: (4)

Do you think this will crack eventually? I have never seen repairs that large with the plastic epoxy repair stuff. Also, I thought the 3M panel bond was to join metal panels. How well does it work on urethane?

KBD85

No I havnt had it crack before, ive been doing this type of stuff for 15 years. And yes it was designed for metal panel repair, but it works so amazing with plastics they even put it on the information sheet if you look up that part number that its good for plastics. So, longevity, ive never had it crack, but i am sure it would fall apart if you dont follow the steps closely. 1- very agressive abrasion 2- good overlap / backing pieces which are aslo very agressivly sanded. 3- make sure its clamped / screwed / held together very well for curing. With these three steps ive had good luck thus far.

Ken

SouthSide2

I have a 90 camaro front bumper that's sunk or low in the top center where the emblem is. Is possible to heat and push it out? Or can it be filled in with Pliogrip? Or a bit of both?
Seems it would take 3/8 build at center and feather out all the way to the head lights. Any thought? Thank you.

SouthSide2

Here's what I'm Taking about.

Thanks for your posts/information. Your work is amazing.

SouthSide2

This may help too.

SouthSide2

I'm in pretty deep as you can see here.

KBD85

Yes I have the same issue on my bird. I have not done it yet, but I was going to do just what you said, sand it realy good with a real coarse grit. Then fill it with the pliogrip. I also had a thought of somehow sparying some of the yellow foam filler on the under side (right stuff is the name of it here) and seeing if that would hold the shape better. Like make my own shape holder like the lower factory shape holders. You know the foam ones and the plastic egg crate ones. That is an area that just isnt supported very well. I hope this helps! and thanks for the compliments! And awesome build!!!! its crazy going all the way, but well worth it. will be so nice when your done!

Ken

KBD85

Base 91. I some how missed your post. Sorry about that. Allot of the primers and paints have come a long ways, any good brand used by body shops will work great. As for me in my body shop days we used "spies hecker". Its probably one of the best products I've ever used. It is extreemly expensive tho. I love their epoxy high build primer, and a product they call "vario". It is most excellent on these rubber surfaces. Now with that said, and me not being a millionaire, I second love Dupont. It lays so nice and flat, where the spies hecker is quite thick and usually needs a good sand and polish. Now, again with that said... Lately for being as cheap as you can and get a decent product, I've enjoyed using omni products. Mind you that usually the quality of the paint is there. The expensive stuff usually has the best matchability for spot jobs that have to blend to existing color. So the less expensive stuff is usually perfect for a complete paint job as matching isn't an issue. As for the flexible clear coat I do still use spies hecker. Its about 100 bucks for I believe their liter, but it is phenomenal stuff. It lasts forever too. You don't need that much, but I think its the smallest container it comes in.

Whew, that was allot. I hope I covered it all, if not, please just ask. I will do my best to answer. I have been out of the profession for about ten years, so there may be better methods, and stuff out there. If your one who knows allot about this, feel free to jump all over this thread. This is for help to every one, so post away!!

Hope this helps... Ken

SouthSide2

I think i have the start of a fix for the deformed upper center of our flexible bumper.

It goes like this. Make a cooling buck... Whats a cooling buck? A cooling buck is a fixture that you place your hot pliable bumper on.

How do I get my bumper hot and pliable? Its easy if you have a 75,000 BTU heater and welding gloves.

I'll work on the buck this week. hope to have pics by Sunday. I have all ready tried the heating part with good response. Need the cooling buck for it to cool and hold shape.

Like i said. I think and hope. Should work.

KBD85

this will be very interesting to see!! thanks for showing us another avenue of fixing these covers.

SouthSide2

This is pic is from Wednesday. I have finished the fixture today. Sunday I"ll see if it was worth all effort. Even if I can't get all the shrink/warp/distortion out. I will still have something to paint it on.

SouthSide2

Here's what I have so far.

SouthSide2

I made some gains in the headlight pocket. The center section not so much as I need to over build the fixture.

I'm probably not going to have time to work on till next weekend.

KBD85

WOW!! OK southside, so if im following you correctly here, you will heat up the plastic cover on this fixture? that fixture looks good enough to bolt on the car anyway, i cant wait to see how this is done. good job so far!!

SouthSide2

I heated up one section at a time (like left headlight area, then right, then center) . Then placed it (the bumper)on the fixture to cool one section at a time.
The heating was done by holding it (the bumper) in front of the 135,000 BTU heater. (I know in a previous post I said a 75,000 BTU. heater, my brother corrected me as he should as it's his heater and it's not a wimpy *** 75,000 BTU heater but a 135,000 BTU heater. All this means is if you have a smaller heat source is will take longer to hear some thing up) .

Cooling it on the fixture was done by holding it in place on the fixture.

My expectations of pulling this off was disappointing as I needed 4 hands

tvc 15

I don't know how we could do it at our level. But the people that refurbish bumpers put the entire bumper cover in a tank of very hot water for several minutes. And when the bumper comes out it's like a noodle and usually returns to the factory shape. On a side note I think the reason some of the bumpers distort like that is because the bumper reinforcement was put on too low and it pulls the crown out of that portion of the bumper.

KBD85

tvc, that is a very interesting thought. I didn't think of that. you are right tho, if these are fastened in a manor that they cant relax in the position we put them on it could cause distortion when they get hot. some times I think it is hard to get them to line up and not be stressed at the same time. what I would love to do, for mine anyway, cuz its customized so much, is make a fiberglass one. that would be new for me tho. very tempting to try.

SouthSide2

This is what we are talkin about.

SouthSide2

I have seen nice/good nose pieces, I have seen bad ones.What the hell is going on? In my option, it is all about the chemical make up of the formual that was given at the day of forming these parts.

KBD85

SS2 i bet there is alot more truth to that than most people think. everything is a little different. Here is a crazy thought. you know that yellow foam we use to fill gaps around the house for holes made by running wire and holes in the foundation ect. I wonder if we sprayed that $#!t behind there for a stable base for the cover to always rest on, then do some body work on the face to fill in the low spots. I wonder if that would hold?? I dont know, just thinking out loud here.

SouthSide2

I'm going to try something like foam or fiberglass. Something that bonds well. Or if i find a good part... Any way it will look good before I paint it and who knows how long it will last? This is a month or more in the future.

nyckid

sweet work