Painting - need some adice and help

[TANKSAREUS]

I have only really painted three of my builds and have had this problem twice.
all the steel I by comes lightly oiled, but for the time it takes to build there is normally a little surface rust.

I stripped down Williams Trike and put a little body filler where needed, then gave the frame a light sand. Then used a scotch brith and thinners, then I wiped it with Laquer thinners then acetone using a clean rag.

The paint has adhered well on most of the frame, except in places aroundthen Engine mount. On my last build it was around the handle bars.

The first coat goes on fine, but the second coat literally flakes of the first coat in places. Its driving me mad.

Question time.
Is my surface prep enough?

I am using a white Luxor primer - not an etch primer - that I can only get in black - is this the right Paint

Do you think there could be oil that penetrated the surface of the metal?

Pics to show what I mean

 

[buckeye]

Use a sealer?

 

[chatten63]

Might try a 180 grit on bare steel. Acid etched the bare steel. Or self eching primer. Scotch brite/220 grit reprime with regular primer sand and paint. I have found using a courser grit on bare steel helps it bite in and hold better. This how I usually do it but everyone has there own way too. Hope this helps. Rick

 

[TANKSAREUS]

Thanks Rick and Tom,

My gut tells me there is residue on the frame of some sort. Pssibly the thinner we use is of a poor quality. I bough a small sandblast gun, going to zap those area to bare metal and see if it helps.

 

[minibikin']

Tank, are you using a final wipe such as wax and grease remover? Thinner is okay to remove the oils and acetone as well, but they are petroleum based and will leave a residue. You need a good final wipe with a non-petroleum based solvent and a good tack cloth.

 

[Havasu Dave]

The paint has adhered well on most of the frame, except in places aroundthen Engine mount. On my last build it was around the handle bars.

The first coat goes on fine, but the second coat literally flakes of the first coat in places. Its driving me mad.

You've got two problems. First one is no adherence to the metal, and the second is your second coat not adhering.

Acetone is petrolium based, but so is lacquer thinner that we reduce paint with. I use acetone to prep bare metal. Where I can't get a rag, I use an old (non oily) toothbrush to scrub. You can also use the lacquer thinner to clean bare metal.

Paint prep solutions work the best, but shouldn't be required for a frame if you clean it adequately.

I always use an etching primer on a bare metal surface followed by a sealer.

However, you can get by with using spray can primer/sealer. If you let your work remain in "primer" for longer than a couple of days, you need to scuff it down, then reseal/prime prior to paint.

You never mention what type of paint you are using. As a general rule, with my high temps, I paint over the primer as soon as it sets. I'm talking two hours in 35C temp with 10% humidity.

I use catalyzed car paint. This is urethane, or acrylic enamel with hardner, and reduced to a specific point, and sprayed with low pressure. The only problem I "don't" have is non adherence to coats. :laugh:

If you paint the first coat and you fog it, the second coat won't stick. Fog means that dry spray-look that you can wipe off with your finger.

The other thing that will mess up the second coat is an improperly mixed can of paint, where the solvents are not mixed. This can create spots in the coat that don't set at the same rate, and it can eat into coats above, or below it.

Bottom line is that you have either water, solvents, or oils being introduced onto your work, and this may be occuring while painting. You may be waiting too long between coats, or not long enough for the solvents to kick.

 

[bikesandcars]

you can get great results with rustoleum as well as high end urethane-enamel, it's all in the prep.

I prefer lacquer thinner (acetone) to brake cleaner. It leaves less residue, as brake cleaner tends to mobilize oil then dry which pushes the contaminates around. It also melts existing paint / finishes. lacquer thinner on a rag seems to clean better.

Always use self-etching primer

Always use a paint system.. if it's rustoleum or dupont.. if you use a system you're covered

I like to heat my items with a torch after wiping with solvent. I use MAP gas and get everything nice and hot. It seems to burn off any remaining solvent residue and condensation on the part. I then paint primer while the item is still warmish (but not hot). Carefully wiping and heating I've never had any of those problem "paint won't stick" small areas.

Watch welds and other hidden areas that can trap solvent and release it back into your paint job.

A sandblasting job works great because it cleans and roughens, sand paper works well too. Depending on what you use for "sand" you may need to wipe the part again anyway, in which case you're really just blasting to help surface texture. I've used black beauty (coal slag) without wiping with anything but a clean rag and have had success.

also don't forget the phospor-zinc type surface prep wipes, POR15 sells one along with others. It's generally recommended between "bright metal" and paint to promote adhesion. That isn't your problem here, but it can certainly help with long term rusting and adhesion issues

my .02

 

[chatten63]

Thanks Rick and Tom,

My gut tells me there is residue on the frame of some sort. Pssibly the thinner we use is of a poor quality. I bough a small sandblast gun, going to zap those area to bare metal and see if it helps.

You are still going to want to scuff it up after you sandblast the areas to help promote the bite into the metal,becareful when sandblasting sheet metal or thin parts so you don't warp and deform any of your work that you have done already.

 

[toomanytoys]

The amount of knowledge here is staggering at times....

 

[buckeye]

Well, thank you.:laugh:

I do agree. The experiences that people share is amazing to a newb as myself.:thumbsup:

 

[WLB]

I like to bead blast the part, prime it with Rustoleum rusty metal primer, and top coat with Rustoleum. Never have had any issues with paint peeling off. If I'm painting over old paint, I rough it up with sandpaper, wipe it down with mineral spirits, prime bare spots, and top coat. I never use anything but Rustoleum for anything I paint--including cars.

 

[maverick1]

I like to pressure wash or take to car wash paying special attention to welds. I use a heat gun to help dry it out.

 

[markus]

Tank, are you using a final wipe such as wax and grease remover? Thinner is okay to remove the oils and acetone as well, but they are petroleum based and will leave a residue. You need a good final wipe with a non-petroleum based solvent and a good tack cloth.

good advice for Tanks problem right there :thumbsup: It also looks like in the last pic your going over some pretty corroded metal to begin with? It that primer high build sandable? and then you are working it all back down before topcoating?

 

[TANKSAREUS]

Thanks lads, will post pics later of how its turning out :thumbsup:

 

[bikesandcars]

Tank, are you using a final wipe such as wax and grease remover? Thinner is okay to remove the oils and acetone as well, but they are petroleum based and will leave a residue. You need a good final wipe with a non-petroleum based solvent and a good tack cloth.

?

lacquer Thinner (which is acetone anyway) won't leave a significant residue that I know of.

Water, citrus cleaner, simple green, etc are the only non-petroleum based solvents I know of, and they involve wetting a bare metal part which leads to other issues.

The more expensive prep-all or wax remover is best utilized over previously painted parts that you are top-coating to remove previous waxes (especially silicon or non carnuba based) as it won't remove or destabilize the existing finish. Using Lacquer Thinner over existing finishes is rolling the dice, you might come away with a rag full of color which isn't good.

Since LT is cheaper, I use that on bare metal and prep products over existing finishes. I use non-petroleum solvents for cleaning parts like aluminum and painted surfaces but not bare steel.

using sandable/buildable primer directly on clean metal isn't recommended, on corroded metal it is almost guaranteed future problems.

using an advanced paint system:
1: sand blast
1a: clean (soap and water, solvent, whatever fits the application)
2: wipe on paint adhesion promoter
3: prime with etching primer
4: top prime with sandable / buildable primer if required
5: seal if not painting immediately
6: paint

Using rustoleum:
1: scrape off loose stuff
2: prime with rusty metal or clean metal primer
3: paint
4: wait eons for it to dry

I like rustoleum, the only downside is the drying time.

I'm not a pro, that's just what I"ve picked up

 

[TANKSAREUS]

Thanks everyone, some awesome advice,

I have a pic of the primer I was using, it not than good, but I found an epoxy primer in a rattle can that fills awesome and sticks like Sh#$ to a blanket. and its cheap $3 a can.

So I blasted the area, wiped with thinners then sprayed with the rattle can, really happy,

 

[Havasu Dave]

lacquer Thinner (which is acetone anyway) won't leave a significant residue that I know of.

At least not in professional body shops. :laugh: Had to say it. (again) Automotive paints are also petroleum based. Even "water based" paints contain petroleum based hydrocarbons.

 

[bikesandcars]

Frame looks great

In the past couple years I've had mixed success with rattle-can stuff you buy at the automotive store or walmart (non-rustoleum). The cheap stuff doesn't seem to resist corrosion or hold up well.

The best I've found durability or corrosion resistance wise is POR-15, but it is expensive and needs to be top-coated.

For a minibike frame you might consider some of the automotive frame paints that are available, eastwood has a nice catalog and selection.

 

[TANKSAREUS]

Frame looks great

In the past couple years I've had mixed success with rattle-can stuff you buy at the automotive store or walmart (non-rustoleum). The cheap stuff doesn't seem to resist corrosion or hold up well.

The best I've found durability or corrosion resistance wise is POR-15, but it is expensive and needs to be top-coated.

For a minibike frame you might consider some of the automotive frame paints that are available, eastwood has a nice catalog and selection.

Thanks for the advice - but don't think eastwood is far east enough to reach SA:laugh::laugh:

I am hoping to slap on a clear coat - that about the only thing that has worked for me. Time and weather are just not playing game