Hi Fellas, thinking ahead a little bit, in anticipation stripping my car... I would like to "clean" up the firewall a bit by patching up any unused holes that I will not need in my resto-mod project. The holes range from small screw holes, to 1" holes. Having never really worked with fiberglass, I would guess that I should use glass matt from the inside, and fill/smooth the outside with ? Was just curious as to any tricks of the trade which would make this a bit easier (ie.. tape on the outer side to hold the matt in, etc... for the larger holes). What would you recommend for filling the smaller screw holes? Any recommendations on repair kits (matt/resin) that I should use? Thanks again for any suggestions. -Ed

 

YES...tape can be used on the outside ...and laminate it from the inside AFTER you have prepped the area well so your lamination time and end result come out accordingly.

With a grinder..you taper the hole from the inside.

AS for a filler when the lamination is completed...I use Vette Panel Adhesive from Evercoat. the quart can is part number 870...the gallon is part number 880.

IF you go and buy this VPA....call Evercaot ad verify their date code method....so you can make sure you are buying good product. TRUST ME....you WILL want to do this.

AS for resin....you can buy the Evercoat polyester resin also.

AS for 'tricks'...I do not have days to type all that I can offer....but if you PM me...I will give you my shop number and you can call me and I will be glad to talk with you.

DUB

 

Thanks Dub, Perfect! I was just reading one of your many post responses regarding the differences between "Matt" and "Cloth"... I'm guessing "Matt" would be the best for this application?

 

MATT---YES!

Cloth can be used...BUT only if you apply at least two layers of MATT first in your repairs...and have the cloth be the last layer on the INSIDE of the car.

DUB

 

Dub, what is a reasonable shelf life for this stuff? One year? Thanks, Ed

 

Hello Dub,
Do you mean do two layers of fiberglass on the inside of the firewall,than put on a layer on the ourside and lastly put the last layer or the inside?
Thanks,
Nelson007

 

Ed,

YES...but....It is hard to say, If the VPA is left in a shop where it gets freezing cold and blistering hot....who knows. General 'rule of thumb' is keeping it at ambient air temperature (70F - 85F). And that 'year' is a good gauge to go by.

I have used it for so long I can open up a can that I have had around for a long time ...that only has about a quart in the gallon can....so there is a lot of air space in the can itself....and just by mixing it...I can tell by its viscosity. I NEVER throw it out because I know here I can use the 'thick viscosity' VPA versus the stuff out of a fresh new can.

Nelson...the repair procedure changes with the location of what you are doing....so...using the large 1 inch hole in the firewall for example....I would PREP the inside so I can laminate. In the process of this prep....with my grinder I grind out about 1-2 inches further than the hole itself. THEN....I grind the THICKNESS of the fiberglass at the hole and TAPER it so it gets really sharp. By tapering the hole so the edge of the hole is now really thin and sharp enough to almost cut you.

I then mask off the engine compartment side of the hole.....and try to put enough tape to provide a good stout surface to laminate on and NOT having the tape wiggle and buckle all around.

IF you are covering a hole that is large and the tape does not want o stay and flexes a lot. Apply ONE layer of matt and resin and allow ti to harden...and the the next day...prep it again and then you are now ready to apply more matt and resin because you now have a solid foundation to laminate on.

Back to the 1 inch hole....So it it taped off on the engine side ...so now you can apply you matt and resin...and because you prepped it so the taper is a nice smooth gradual taper and comes to a sharp thin edge on the inner edge of the hole.....when you apply the 2 layers of matt and resin.....you can apply one layer of cloth. The cloth will provide serious linear strength. Let that harden. Peel the tape off the engine compartment side.....prep with your grinder and fill it with Vette Panel Adhesive. BUT this is for a hole that is NOT on the exterior of the car.

When filling in holes for old luggage racks or whatever when they are 3/8'' and larger. When I went to prep the exterior..I would grind the exterior out a bit further and then apply one layer of matt and resin...and when that hardens...prep it again and then fill it with VPA.

DUB

 

Dub ,
I sure apreciate the information that you posted, it is very helpful.
I have been restoring a 1970 LT1 for 3 years and have been using your post to help me finnishi the car.
Is the 1970 firewall pained with flat black?
Thanks,
Nelson007

 

I am sure it looks great!

DUB