Use of Bondo on engine

[tbirdman]

After stripping away the old paint on the engine and accessories, I see the previous restore had used bondo to cover rust pts etc. I have used Metal Glaze in the past but find it hard to sand. Any thoughts on using bonding for filling imperfections?

[West Peterson]

I like to see rough casting imperfections and generally take points off for smooth crankcases.

[Guest imported_Speedster]

It really depends on how big the holes are and how hot the piece gets, as to what is best to use?

There are some 2 part Epoxies (2 equal parts) that bond well to Metal, but they are best for Larger holes and Imperfections and they can take High temps.

For the smaller holes Bondo and Glazing-putty bonds well to metal as long as it doesn't get to hot.

Thick primer paint works for smaller holes.

[tbirdman]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: West Peterson</div><div class="ubbcode-body">I like to see rough casting imperfections and generally take points off for smooth crankcases. </div></div>

The question is what are casting marks and what was put in some one else. On the crankcase, I have two areas that exhibit a circular machining marks. On the head it looks like at one point some one had trouble removing the head as there are gouges in various spots.

I don't plan to use bondo all ove rthe engine. My areas that I wante dto use it wa sto smoth out the head and also fill the pits in the road draft tube etc.

[tbirdman]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Speedster</div><div class="ubbcode-body"> It really depends on how big the holes are and how hot the piece gets, as to what is best to use?

There are some 2 part Epoxies (2 equal parts) that bond well to Metal, but they are best for Larger holes and Imperfections and they can take High temps.

For the smaller holes Bondo and Glazing-putty bonds well to metal as long as it doesn't get to hot.

Thick primer paint works for smaller holes.

</div></div>

I just did the first couple coats of high build primer last night and would like to use that if possible. I have used metal glaze on a overflow tank for my T-bird, and it has held up well. When I was first starting out, I had some one blast and paint the some t-bird parts. He dropped the overflow tank putting a big dent in a corner of it. Rather than pay for a new one, he told me "now you'll learn how to do metal repair"

[Restorer32]

I have yet to have anyone explain to me the real difference between so called "hi-temp paints" and regular paint. We fill any holes or imperfections caused by rust or mishandling over the years but generally leave casting marks and inperfections. We have found that regular straight enamels hold up just as well as the expensive "engine enamels" on blocks. Your results may vary.

[Guest imported_Speedster]

There's Also (2 part) Epoxy-paint, which is good at high temps and is very durable. There's not many colors to choose from but it is very good as a primer/filler.

[tbirdman]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Restorer32</div><div class="ubbcode-body">I have yet to have anyone explain to me the real difference between so called "hi-temp paints" and regular paint. We fill any holes or imperfections caused by rust or mishandling over the years but generally leave casting marks and inperfections. We have found that regular straight enamels hold up just as well as the expensive "engine enamels" on blocks. Your results may vary. </div></div>

Seems like everyone uses Bill Hirsch's green Packard enamel.

Was the Packard head general pretty smooth?

[Restorer32]

We used to use Bill's engine enamels 'til we noticed that no two cans were ever exactly the same color. Packard heads were pretty nice castings from the factory, yes.

[Dave Mitchell]

We use Imron matched to Packard engine green as it holds up best to oil and gas, but probably a good quality single stage paint would do almost as well. We also fill damaged areas and leave the normal castings. It is tricky if you have to fix one area and not another to get it all to look uniform again. You can use MarineTex as a filler as it will stand up to engine temps better than other two part epoxies like JB Weld, otherwise good quality primers. I agree that the heads were fairly smooth, at least the earlier ones.

[tbirdman]

OK if you guys don't like Hirsch's engine enamal, how do you match a good single stage enamel to a Packard green?

I only want to paint this think once, and what it to be durable as possible.

[Guest imported_Speedster]

I Like Hirsch's engine enamal. I've used it on 4 engines and had No problems with it. It's easy to apply, flows well. It's durable and high-temp resistant. And it Looks Good.

[tbirdman]

OK I'm ready to paint the head. DO I go with the Hirsch engine enamel or do I go with a single stage enamel?

My main concern is longevity and durability.

Not sure what it was painted with before but it seem to come off fairly easy.

[Restorer32]

If you are just doing one engine and you will be painting everything at the same time, we would go with Hirsch. Just bear in mind that a couple years from now when the engine needs touching up that the available "Packard Green" engine enamel may not be exactly the same shade.

[tbirdman]

Well have a quart so that should do about 10 engines. Just have to make sure I seal it.