Author Topic: Painting Question (Read 2070 times)

rocco · « **on:** November 05, 2015, 07:45:51 AM »

Hello all,

So I cleaned my engine up, degreased it, wiped it down with acetone and sprayed some PlastiKote high temperature paint on it.
It was around 16C (80F) outside where I did it, the lower limit for temperature to use the can. It sat in my garage overnight at around 70-75F. 24 hours later the paint was not completely dry to the touch. I brought it into the house, and another 24 hours in here and it still is not dry. You could touch it and be alright, but actually handling and moving the parts or running your finger across it and it will get on your fingers and dull the paint. The can says it should be dry to touch after 1 hour, no baking required.

My question is, I've never painted metal before. If it is still not dry at this point, will this affect the final adhesion strength of the paint? Should I cut my losses and strip it for a new paint? Or should I wait a few more days and see if it dries? Are long dry times on metal normal? I know my Tremclad(Rustoleum) that I painted at the same time on the side cover is dry and good to go under the same conditions.

I attached a picture, I'm nervous because I was really happy with the outcome, just want it to stick!

Thanks, Reilly

flybox1 · « **Reply #1 on:** November 05, 2015, 07:58:55 AM »

Plastikote?

Isnt that plastic?
Why not something that's actually preferred for painting engines....like engine paint.

edit:
I checked the website and I guess it should work. Mix it well enough?

rocco · « **Reply #2 on:** November 05, 2015, 08:03:19 AM »

Quote from: flybox1 on November 05, 2015, 07:58:55 AM

Plastikote? Isnt that plastic?
Why not something that's actually preferred for painting engines....like engine paint.

edit:
I checked the website and I guess it should work. Mix it well enough?

Haha, yes it is for engines. I mean, I shook the can, what more can I do?

Sent from my LG-D852 using Tapatalk

madmtnmotors · « **Reply #3 on:** November 05, 2015, 08:11:41 AM »

Quote from: calj737 on November 05, 2015, 08:05:35 AM

Another option, is to make a DIY hot box. Foil line some cadboard to encase the motor. Use a heat gun poked in thru one end, and turn it on and let it rip for a while. It should create enough heat in the box to raise the curing temperature enough. It may also "shrink" the paint, so that would be a good indication of full cure.

I was thinking the same thing. In lieu of a heat gun, you could use a shop light with a 100 watt incandescent bulb (if you can find one)...

a 100W fluorescent or LED won't generate enough heat.

flybox1 · « **Reply #4 on:** November 05, 2015, 08:13:12 AM »

I think event without a primer, it would have cured hard to the touch, but just not adhered properly
At those ambient temps, the acetone would evaporate almost immediately.
Surface contamination was still present... or not mixed well.

Hot box is a good idea, calj.
I cured my engine enamel @ 250F for 30 minutes.

rocco · « **Reply #5 on:** November 05, 2015, 08:52:29 AM »

I'm almost sure that the acetone evaporated without a problem. It was evaporating from the sheet I had down around the engine before I painted. I spent hours and hours making sure it was very clean and oil free so I don't think that's the problem.

Temperature maybe was too low or mixing issue I guess. Repainting sounds horrible right now. Would like to save it if possible.

I have a heat gun. Is any Aluminum Foil good enough?
As for the cylinder block, head and cover, I could throw those in an oven and see if that helps?

madmtnmotors · « **Reply #6 on:** November 05, 2015, 09:04:54 AM »

Quote from: calj737 on November 05, 2015, 09:01:08 AM

You could first attempt the cylinders in the oven, 200-250* for about 45 minutes should be a good indicator. Let cool, then test for cure-

Be sure to support these by the aluminum cylinder block. If you just set them on the rack, standing on the bottom of the steel sleeves, there have been instances where the aluminum cylinder block has slipped off the steel sleeves.

rocco · « **Reply #7 on:** November 05, 2015, 09:16:03 AM »

Ya calj, that's what I was thinking before I go spending time on making a foil box. Test it on the small part in the oven first. Thanks, fingers are crossed. It's too cold to paint outside for the rest of the year and I've got no place to do it here. This is my last hope.

madmtnmotors, i'm not sure I understand what you're saying. I'm just going to throw the pieces on a try into the oven.

Powderman · « **Reply #8 on:** November 05, 2015, 09:23:59 AM »

16C is 60F, 80F is 26C. If it was only 16C it's too cold for paint to cure quickly.

rocco · « **Reply #9 on:** November 05, 2015, 09:29:06 AM »

But can it eventually cure is my question?

Is it safe to do this in a home oven haha?

madmtnmotors · « **Reply #10 on:** November 05, 2015, 09:29:48 AM »

Aluminum and steel expand at different rates when heated. If you stand the cylinders "right side" up then they will be standing on the steel sleeves. There is a slim possibility that the aluminum cylinder block could slip down on the steel sleeves, or in other words, the steel sleeves could effectively "pop out" of the aluminum cylinder block. The steel cylinder sleeves are pressed into the aluminum cylinder block from above.

Just playing the devil's advocate here pointing out the worst possible scenario. I'm sure others have done it without issues.

But that doesn't mean it can't happen...

rocco · « **Reply #11 on:** November 05, 2015, 09:34:16 AM »

Right, gotcha, ya no, I put it with the flat side down. Should be good!

Powderman · « **Reply #12 on:** November 05, 2015, 02:15:16 PM »

I don't think you want to cure it at that high of a temp, I would not exceed 150*

rocco · « **Reply #13 on:** November 05, 2015, 08:15:11 PM »

Well I tried making an oven, then I convinced the lady to use the actual oven. Neither of them worked. It's still not dry to the touch. So I guess I'm stripping it down.

This time I will be using a primer. Is any self-etching primer okay? Or does it have to be high-heat? What's the difference between an engine paint and an engine enamel?

przjohn · « **Reply #14 on:** November 06, 2015, 07:16:17 AM »

I would recommend switching paints to VHT brand if you are going to go through the trouble of repainting. VHT is probably the most popular engine paint out there. You still need to cure it but it will dry like ordinary paint and if you are careful not to get any gas or fluids on it the paint will cure with just running the motor.

flybox1 · « **Reply #15 on:** November 06, 2015, 07:24:35 AM »

Duplicolor Engine Enamel.

rocco · « **Reply #16 on:** November 06, 2015, 07:59:54 AM »

Haha oh yes, I am definitely changing brands. I sprayed the whole this does with paint thinner, it came off like nothing. I've never see paint leave a surface that quickly before.
Quick question though, isn't paint thinner oil-based? So do I now need to be very sure I get it all off with acetone before painting?

The reason I chose that brand was because they had no VHT in aluminum or Dupli-Color Engine enamel in Aluminum and the store near me. The Dupli-color is some weird metallic green colour. VHT only has black. Do the VHT and Dupli-Color require primers?

flybox1 · « **Reply #17 on:** November 06, 2015, 08:23:07 AM »

you'll need to basically wash and scrub your cases with acetone.
spray bottle filled w acetone, plastic bristle brushes....spray, scrub, spray, repeat...
paint wont adhere until nothing comes up with a white cloth/acetone over your finger.
No primer needed w the duplicolor. They have a silver/gray that closely resembles original case color.
Spray on per the directions and cure in the oven/hot box.
My cases withstand gas spills, and clean well with simple green.

rocco · « **Reply #18 on:** November 06, 2015, 07:36:28 PM »

Update from the painting noob.

So, after waking up early to remove all the paint and get ready for painting again. I was in a rush because today was the last day it would be warm enough to paint for the rest of the year. I went ahead a got some DupliColor Engine Enamel 1615 aluminum as well as a Self-Etching Primer because I was determined to make this friggen thing stick.

So I warmed up the engine in my hot-box and shot it with the primer. Let it dry for 35 minutes as directed and then began with light coats of paint with 10 minutes between as the can directed, Keeping it warm with a heat gun.

Everything dried! It's a miracle! I will be cure it tomorrow in my heat-box. However, here is my question. My paint looks more like a flat-gray than a shiny aluminum. Now, I didn't sand the primer before painting, which I'm thinking could maybe be the reason. I don't hate the look, it's different. But I'm just wondering if it will be just as resistant? Also, I accidentally shot the sproket with a bit of paint on one pass, there was a gap in my tape. Will that be an issue?

rocco · « **Reply #19 on:** November 07, 2015, 06:42:14 AM »

Quote from: calj737 on November 07, 2015, 04:36:37 AM

You could use a rattle can clear and cover the grey with a semi gloss if you're so inclined. Lustre is a result of the paint, not the primer. The sprocket will be fine. You need to wipe it down to remove the rust and grime anyway before you reassemble. Just carefully use some Paint Thinner on a rag and go slowly. I rather like the look of your engine personally.

It's actually grown on me through the night, looks great in the morning sun! Thanks everybody!

750K · « **Reply #20 on:** November 07, 2015, 07:16:07 AM »

I've never found aluminum spray paint to be very shiny looking, not like silver at least. I bet a combination of cooler ambient temps and aluminum's already semi dull look it went a bit flatter, should brighten up in the sun I bet.

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Author Topic: Painting Question (Read 2070 times)