Front fender Repair

[FarmerSid]

Hey All! Been working on repairing the rust on my front fenders on my 51 Chev truck. I'm at a point where should I repair back to original or repair to look original but eliminate the factory lap joints. I have repaired the factory mounting flange where the front fender meets the cowl but from the factory there is a added strip so to speak tack welded on the inside of the flange all the way down under the cab. I have replicated that as well but now that it is ready to be tack welded in, I'm thinking maybe I should just extend the flange by butt welding it on instead of the lap joint. I don't like lap welds one bit! Just a honey hole for moisture to hide and form rust. What's are you all thinking?

[FarmerSid]

Somebody must have an idea what I'm up against. What do you all have stored in your heads...............?

[mr48chev]

I'd do what ever I felt gave me the best outcome and the best chance of keeping the rust down in that area. It is a problem from what I have seen but the area does need to be reinforced.

[mknittle]

I would lap weld and seam seal.

[FarmerSid]

I think I'm going to lap joint the the new parts back on. Looks more original. I'm very pleased on how the new pieces I made turned out. I will get some pictures up of what I remade. Should I epoxy paint the lap joint before welding the new pieces back on?

[mknittle]

Originally Posted by FarmerSid

I think I'm going to lap joint the the new parts back on. Looks more original. I'm very pleased on how the new pieces I made turned out. I will get some pictures up of what I remade. Should I epoxy paint the lap joint before welding the new pieces back on?

Paint will contaminate the weld. causing all sorts of problems.

[crossfire84]

Originally Posted by FarmerSid

I think I'm going to lap joint the the new parts back on. Looks more original. I'm very pleased on how the new pieces I made turned out. I will get some pictures up of what I remade. Should I epoxy paint the lap joint before welding the new pieces back on?

use a weld through primer.

[FarmerSid]

Hey all! Been awhile but have some finished fenders. I've read that many recommend spraying the inside of the fenders with box liner to prevent stones or gravel from flying off of the tires and making dents on the outside finish. My fenders are are all sand blasted and ready for spraying. Should I spray the box liner on before paint or after? A step by step procedure would be great for the stage I'm at now. A buddy says I should spray the mounting areas with paint first then assemble and then paint the truck after assembled. I'm not sure that would be best. Opinions please...

[_Ogre]

i brought all my parts to be sprayed with a thin coat of rhino liner bed liner for that exact reason.
use any bed liner vendor, the rattle can stuff is real thin, even 3 coats is real thin and easy to scratch off.
i had my front and rear fenders, inner fenders and the bottom of my cab rhino lined.
i talked to the local vendor after sand blasting all my parts, he recommended bare steel, his primer and liner
do all your bodywork first or at least close enough so your only priming and spot filling.
you can also tint the bed liner, black looks best imo.

rear spare mounted fender, pic shows applying welt with double sided tape, but you can see the bed liner

[Stepside Jim]

Originally Posted by FarmerSid

Hey all! Been awhile but have some finished fenders. I've read that many recommend spraying the inside of the fenders with box liner to prevent stones or gravel from flying off of the tires and making dents on the outside finish. My fenders are are all sand blasted and ready for spraying. Should I spray the box liner on before paint or after? A step by step procedure would be great for the stage I'm at now. A buddy says I should spray the mounting areas with paint first then assemble and then paint the truck after assembled. I'm not sure that would be best. Opinions please...

FarmerSid, I have tried the idea of skipping the epoxy primer, then paint, then spray can bed liner process and opted to sandblast then spray can bed liner.

I can say....I will not do it again. The bed liner stuck to the sand blasted very well but it was not a total block for moisture getting to the metal.

I built a really nice crossmember for a 50 Willys truck, being in a hurry I blasted and applied 3 coats of the spray bed liner. It looked great, wow what a time saver. This past winter we had a snow storm, I drove the truck to ensure I got home after work. It seems the road pea gravel mixture they put down had a bit of salt mixed it. Shorty after that I could see how the salt residue got to the metal and created rust specks.

After this I will always follow the whole process of priming and painting.

As for the professionally applied bed liner such as _Ogre did with rhino liner, it is a different story, it will probably do a much different job than the spray can stuff.

[FarmerSid]

Thanks for the replies. I'm a bit confused and don't understand what you two are saying. Should I be epoxy priming the whole fender in side and out first, apply bed liner to the inside of the fenders and then paint the outside of the fenders in the final colour I want the truck to be in?

[skip99]

Read through a couple builds, and you will learn a lot,
If all the metal is bare, do your welding, grinding and smoothing, then epoxy everything, top and bottom, you can even pour epoxy into hard to reach areas,.
If your metal is straight, wait a few hours or overnight and spray primer, or I like to use feather fill and block it, if metal is banged up, do you bodywork , either on the epoxy or grind it to metal, your preference ...
If you have a few pinholes or rust through s, use some dura glass first, it is waterproof, then filler on top. Of that...
I just switched over to 3m platinum plus, I like it better than rage gold, and it's half the price, cost was not a factor, I just like it better, it sands better,,,,
I spray most parts while off the vehicle, just looks better....just be patient while assembling, I also put the whole vehicle together for alignment and fit check before taking it apart and painting. Look at my build, that 51 has been put together at least 4 times...
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If you want to paint the truck all together, just tape it off when done and spray the undercoat after....epoxy will just need scuffed with a pad...

[FarmerSid]

Thanks Skip. The fenders are all repaired, hammer and dollied and smoothed out. They are freshly sandblasted and ready for a coating of some kind. I'm just a bit confused on what to do next. Should the bedliner go on bare metal or should it go on over a primer? Should the bedliner go on before the finished colour?

[Stepside Jim]

Sorry FarmerSid, I guess I wasn't clear.

I would epoxy prime everything inside and out. Epoxy is a great barrier and sealer.

I'd even go so far as to painting over the epoxy inside and outside. After the paint has dried, scuff it with the recommended grit by the bed liner manufacturer and apply the bed liner where you want it to be.

This will be the order of which I will follow from now on.

Now I have the moisture barrier of both the primer and the paint along with the chip resistance of the bed liner spray.

Be sure to allow the paint to dry fully, I've found that if the paint has not dried fully, there will be a reaction when the bed liner is applied too soon.

[skip99]

Originally Posted by FarmerSid

Thanks Skip. The fenders are all repaired, hammer and dollied and smoothed out. They are freshly sandblasted and ready for a coating of some kind. I'm just a bit confused on what to do next. Should the bedliner go on bare metal or should it go on over a primer? Should the bedliner go on before the finished colour?

Epoxy really sticks to sandblasted. Metal...epoxy it all,,,,,
I would spray undercoat or Bedliner after all color and buffing is done. And it can go right on the epoxy...
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[FarmerSid]

Thanks guys! Makes sense now. Please don't be sorry for anything. I'm a bit slow and takes me a bit for things to sink in. Another quick question for you all. Is high build primer and epoxy primer the same thing? I have the fenders to a point that I don't need any body filler. If I understand things, I now need to spray 2-3 coats of high build primer and block sand in between coats to even things out. After that, spray some paint. Am I close?

[skip99]

It's a 51 Chevy truck, there is not a flat spot on it ! Trust me, I know...

Spray epoxy
Wait a few hours or til next day..
Spray a few coats of primer.
Block sand
Reprime if needed
Final sand
Paint.

Now...I would suggest feather fill over epoxy , before urethane primer. It is spray able polyester, like bondo, but you can block it very quick and straight, use 180 grit to cut it straight first, then just go finer , to say,,,320 , then spray urethane primer, block again, but start with 320 , then wet sand to 400 or 600 ,
Then paint.
Buy a good flexible block for those curved panels, afs blocks are great.
Dura blocks are too stiff..
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[FarmerSid]

I hear ya on the flat spots! I will look into the products you mentioned in my area and see how things go. Thanks again.

[gale]

Originally Posted by FarmerSid

Another quick question for you all. Is high build primer and epoxy primer the same thing?

No. The 2K High build goes on OVER the epoxy.

A lot of good painters use a self-etching primer on bare metal and follow that with 2K high build primer. The etch primer is used ONLY on bare metal whereas the epoxy primer works on bare metal and paint.

Sandblasting is OK but 40 to 80 grit paper works well too.