When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I’ve been cleaning the engine bay with stripper and lacquer thinner, but I’ve got an area I’m not sure what to do with. I assume battery acid did the damage because it’s in that area. The paint is gone and the fiberglass is rough. What can I do to this area to correct it? In addition, how should I finish the prep and paint for the engine bay? I have Krylon 1613 Industrial for the finish, but do I need to prime? Here is what I am working with.
The first picture shows the firewall damage I am concerned about. If is solid, but is very rough to the touch. What can I do to smooth it out?
As background, the body is off due to a rotted frame. New Vette Products frame, so trying to dress up the engine bay to match the clean and freshly painted frame and engine. It is NOM, no judging, just want a clean, safe and secure driver.
Thanks for your help!
Barry
Here is the acid damage?
Last edited by Hermn59; 11-05-2018 at 03:01 AM.
Reason: correction
If the fiberglass is rough and somewhat fuzzy. I would pick at it with a sharp tool and see if the fibers begin to fray out more and more when you rake the tool across is with some pressure..
If the fiberglass begins to fray out then that is telling me that the resin has been damaged and the only way I know you can fix this is to get that bad area sanded down to it no longer allows the fibers to get fuzzy and seem to want to collect up like cotton ball fibers.
Once that area has been sanded. and COMMON SENSE does come into play here. So if you are sanding and sanding and the fiberglass is still coming off really easily and fuzzy . Adn you feel that you are going to sand through the panel....THEN you might need to stop and then apply a mat and resin on the areas while you still have the basic shape of the inner skirt still there to go off of. I would use 80 grit with moderate pressure when sanding.
Keep in mind the mat and resin is only good IF you apply it to GOOD fiberglass. Now.. If for example you sand down this area to where the fiberglass is about the thickness of piece of paper. I would stop and apply mat and resin even though I know I am contradicting what I just wrote on how fiberglass needs to be applied on a good surface.
But with almost all of the bad fiberglass being removed ...and the panel now being so thin. you will be putting back a good amount of material to replace what you just removed. And that paper thin layer you are applying the mat and resin to is not a concern and it will be fine. Because you are using it now as a foundation for your fresh mat and resin.
How much of an area you sand and laminate on is up to you and the main thing is to not loose the shape of the panel if at all possible. So depending on how bad the fiberglass is. this area could take several applications to get it repaired instead of trying to do the entire damaged surface area in one application due to the panels shape.
If you sand or grind on it and it turns to a powder then that is telling me that you are down to good fiberglass. Then pick at it again with your sharp pointed tool and see if it glides on this area like it should on other areas of your car that are not like this.
Now... IF you need a primer or not. that all depends on how nice you want it to look. I can say that any remaining paint from the factory on these panels could cause for paint reaction so test it before you jump in and just spray it out like crazy. Fresh paint and the solvents in it and how HAEVY you apply it on each coat can soften/loosen and possibly cause for the paint that was left on the panel to wrinkle up badly.
Thank you for the guidance. I just got home from work and will not get a chance to work on it tonight. I hope to get to it tomorrow, so I will give you an update of what I find.
Thanks again for sharing your knowledge and experience.
I took a putty knife and raked it across the fibers with pressure, and everything seems very crisp and hard. There is the texture of the fibers, but none seem fuzzy at all. I used the corner to pick at individual fibers and got the same crisp scratching. Here is another photo that shows the lightened areas that I scraped. Pushing on the area with my hand causes the entire panel to bow in slightly, but not like the area is weak or compromised. But then again, I am no expert.
I hit it with 80 grit and don’t see any fuzzies, but I may have a different problem. There is an area with cracks and flaking that doesn’t seem right. I tried to capture it below.
See if this effect is the same on the other side of the panel. Some times these cracks do not make it through to the other side.
So..it is possible to sand on it and get the flaking to stop. Depending on how large of an area and where the area is located it can be filled in with VPA or mat and resin....so it depends.
The inside has carpet backing, jute, glue, or all of the above that I need to get scraped out. I was able to get through in some places and it appears the inside is not cracked or flaking like the outside. I found threads that state 3M Adhesive Remover is good to use to help soften it up. Do you agree? Any other tips or tricks?
Once I get the floorboard cleaned, I will shine light from the engine bay (saw an expert do this in another thread) to get a better idea of the condition. More to follow.
When it comes to removing old glue. I use automotive grade lacquer thinner due to it is cheaper than the adhesive remover. I wet the area out and let it soak in. Depending on how thick the glue is...it may take several application to get it loose enough to come off. There will be a point to where the glue can easily be rolled off due to it is not too gooey. Play around with it and you will see what I mean. If you go into soon...the glue will get like snot...wait a bit longer and it will roll off.
Depending on how thick the factory glue was applied. I have taken sheets of Bounty towels and got them wet and put them on the area to allow me to keep it wet with the thinner.
Like I would tell my guys...let the solvent do the work for you and try not to rush it.
I should have waited for your latest post. I am impatient, and now nauseous.
The inside is slick and not flaking, and I am not sure what the light shining through shows. Do I need to get more of the firewall paint off to tell for sure?
The car must have been born blue, Frost Blue maybe? I have found the blue on the floorboards, firewall, dash, and inner fenders. Someone took the time to change it all to red.
I did some additional cleaning on the firewall, so here’s a couple new photos. The light is shining directly in the area of the flaking. The tape in the second photo is to identify one of the flakes, but I can’t really see it from the inside.
Am I not getting aggressive enough in then corners/low spots? I see some that are nearly spotless, but I can’t seem to get the corners clean.
Are you just showing me what you see or are you wanting for a reply to a possible type of repair??.
The one thing that is clear. The contaminated area is well shown due to the light will not shine through it versus the area of good fiberglass where light does glow through it..
It is now questionable if this contaminated area will hold paint for any extend period of time or not.
Sorry, I absolutely would appreciate your advice on how to repair the area. I was trying to give you the best idea of what it looks like without it being in front of you. This is going back on a new Vette Products frame, so I am trying to make sure everything is solid, safe, and looks good when I am done.
Well logic and common sense come into play here. KNOWING that the dark stained area is where you had the problem with the battery acid...but yet the fiberglass seems to be solid. I would remove it like I had previously mentioned. Regardless if the fibers fuzz up or not due to these photos show the stain in the fiberglass that you did not show before. So more information to draw a conclusion on how to repair it. Grind and apply fresh material so the surface that the paint is going on will have no chance of it falling off due to it is not effected by the acid. I wrote it out back in post #2.
Or scuff and primer this area after doing some slight filling and hope for the best.
I have been studying your posts throughout the Paint/Body forum to glean further knowledge. I have spent a lot of time on your John Lingenfelter thread. Thank you, as that is extremely helpful.
Although I understand fiberglass a little better, I could still use your advice. I ground out the contaminated area and believe I am ready to proceed. Some of the area came out as dust, and some came out in dry flakes/chunks. I ground until all of the dry flakes were gone and everything seems uniform. Below are before and after photos from the passenger seat.
Some of the area is paper thin, so I think I need to lay in some sheets of mat and resin. If this is the correct method, can I lay more than one layer at a time since it is on the upward slope of the floorboard?
YES...you can lay more than one layer. But it all depends on the area where it is paper thin;...when you go to try to get all the air out of the mat and have it not sopping wet in resin ( which is NOT good)...can cause for this paper thin area to fracture and ruin it beign able to still have the correct shape you still want to retain.
SO...it all depends. If it can handle you working out air then apply 3 layers...if not...apply one so it gives that area strength again so the next day you can come in and grind it for the next layers have something to bond to.
Okay, so here’s the reveal. The horn mounts were both broken out so I thought I would start on something smaller. I want it to be right, so constructive criticism is welcome. If I need to cut it out and start over, so be it. If ready to proceed, direction on next steps would be appreciated.
LH upper inner fender (wheel well) prep; tape placed here (thanks to cool tool) LH horn mount laminated LH upper inner fender tape removed RH upper inner fender (wheel well) prep; tape placed here (thanks to cool tool) RH horn mount laminated RH upper inner fender tape removed
11-04-2018, 08:18 PM
C1 Engine Bay/Firewall Battery Acid?
It’s gonna be epic!
