Ben Hart
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Well, I do collision, not restos, but:
I would avoid grinding or anything producing much heat (including sand blasting) since it can warp the panels to sh**.
When I strip at work, I will grind if it is a small area and not too flat. Larger areas like hoods I always chemical strip.
The other problem with blasting is that you can never seem to get rid of all the media after no matter how well you blow and vacuum it our. I used to do sandblasting on heavy trucks and it was always nasty. There would always wind of being some sand in the booth and inevitably in the paint somewhere.
Soda blasting is a great way to remove paint, but does nothing for rust. I think some places use walnut shells or plastic media as an alternative.
I don’t know a lot about dipping a car, but I do like the idea of it.
My top 2 favourites are Lesonal Pro Air clear and Nason. The Lesonal is better than the Nason and probably more durable.
The Lesonal is great for air dry situations and has a few different activators so it is great for large jobs or spot repairs. I can just about gaurantee they you’ll like using it and love the finish.
[quote=”Stone” post=15469]actually (paint match and blend) is on most estimates we do and I know real painters always check their match, tint and spray, spray outs regularly and if in doubt, blend it out, if they care at all about the color match :whistle: …. :dnc[/quote]
Definately old school thinking.
I think the proper process is to mix the standard (not worrying about over pours, unless someone is watching). Blend the colour and hope for the best. If it turns out poorly you consult the excuse catalog and select the best excuse for the situation, provided it hasn’t been used in the past 72 hours.
“…well, it looked good in the booth…” 😛
This all seems to be good info.
However, HVLP is required in many areas since it has better transfer efficiency (i believe at least 65%) than a regular gun. As Macioce said, less overspray and wastage. The problem with HVLP is that because the pressure is low, it can be slow spraying and when spraying clears and S.S. you may have to work a little harder to achieve the desired finish. HVLP is limited to about 10 PSI at the aircap.
Conventional guns need to meet no regulations and can be sprayed at any pressure. Often 45 PSI (at the regulator) and up. The transfer efficiency is often below 30% (so if you spray 1 quart of paint, just over a 1/2 pint will actually make it to the car and be useful).
HVLP has been around for a long time. At some point after HVLP guns came out, paint gun manufacturers introduced a new style of gun to solve the problems of HVLP guns. These guns are usually referred to as compliant guns. These guns offer the same (or better) transfer efficiency required of HVLP but often can be sprayed with a little more pressure (at the regulator) and put out greater volume, thus faster speed. These are very popular guns (such as the SATA RP, Devilbiss Plus etc). Most compliant guns can be used in areas requiring HVLP, so long as the gun can meet certain restrictions (typically the same max 10 PSI at the air cap and equal or greater transfer efficiency).
Basically you need to select the appropriate needle/nozzle size for the product you are using as well as the appropriate air cap. This info may be avaliable from your gun manufacturer and/or your paint manufacturer. Some cheaper guns and cheaper paints do NOT offer this info. Trial and error as well as experience can help you out.
Most top coats (S.S, basecoat, clearcoats) as well as sealers spray well with a 1.3mm tip, as a starting point if no info is avaliable. Primer surface is usually good with a 1.8.
Gun pressure should be read at a regulator at the gun, while the trigger is pulled. Gun pressure with vary a lot depending on the gun and material you are spraying. Again, refer to tech sheets for a starting point.
Now that the gun is together with the correct components, in good working order and hooked up to a good air supply you can put your product into the gun and spray against a test panel or some masking paper.
Open the fluid needle all the way, then turn it back in 1/2 turn. Open the fan all the way. Pull the trigger and set the air pressure as recommended. Spray at one spot for a brief moment. The spray pattern should be even and have an consistant shape and consistant coverage from one end to the other. The exact size and shape will vary with air cap and gun. Now do the same and spray horizontally. The product should build and cover evenly without running. Do the same horizontally and hose it on until it runs. When it runs, it should run evenly acoss the whole spray pattern. Make a few passes as you would painting a car. Look at at and see if it meets your standards. Let it flash/dry a little to see if it runs or sags. If you are happy, the gun is ready to spray. If not, you will need to adjust either the fan size, fluid and/or air pressure.
Air pressure, if set appropriately probably won’t change much. The fan may be dialed in a little if needed, and fluid needle may be turned in more to adjust your spraying speed.
Adjust it to what suits you. Your technique will be congruent with the set up (gun distance from the panel, speed, overlap, etc). This is the procedure for spray the gun at full capacity. If you are spraying a small area, adjust as needed following the same basic steps. There are a lot of variables, but once you get used to it a certain way, you won’t adjust it much from there.
I can help if you want.
I have been an administrator on another forum for about 7 years. I haven’t been too involved with it in the last year or so due to other interests.
For about 2 years I did some webpage design (using Frontpage). I haven’t used Joomla, but I have used a few other formats. I am sure it would be easy enough to figure out.
Let me know, and if you want I can send you a link to what I have done. The only thing I can’t guarantee it how much time I can put in, but I certainly would be able to assist regularly.
With PPG and DuPont I have used many different aerosol primers under water base. Mostly the DuPont and PPG self etching primers, though.
Obviously there are better products, but for small burn throughs and the odd unseen part (like a small repair on a rad support) it has worked very well.
Have you actually tried it with the Onyx?
I’ve mostly used Norton and 3M (the 2 most common, here at least). I would definately go velcro, stick it is more of a pain, especially if you don’t completely use up your piece of sandpaper everytime.
I like 3M better, particularly in the finer grits. The new hook-it is great paper, better than Norton when I did a side by side comparison.
But…I don’t pay for it. If I were just doing the odd job at home here and there I would go with Norton. It is more than good enough.
Besides, with the Velcro pad you can switch between whatever brands if you want. And as Ryan said, Hook-It 2 is almost dead, don’t bother with that route
Looks like everyone has given some great advice. The old paint is a great substrate and if the sealer and clear had flex additives in them, then a second paintjob overtop will not make it crack easily.
One note, do you use anything to reduce static on your plastic parts? Static can make the flakes lay flatter which may make the paint look different than your spray out card (not to mention the added dust it attracts).
Oh, as far as the “greyness” when sanding the clear…you are probably just seeing the dust on the surface. If you clean the panel properly it will be like normal, just not glossy. Clearing over will bring back the gloss and make the colour appear as before.
Well…
You need the appropriate grit for adhesion. Generally a coarser grit gives better adhesion (since it cuts deeper and creates more surface area). However, the products you are using will only cover so coarse of a sand scratch.
Final sanding prior to applying basecoat will vary by brand, some (like DuPont Chromabase) can cover 400 grit. Most people sand finer, however, especially on metallic colours. There is also a difference if you are sanding dry or wet or with a DA sander. If you are wet sanding, I would finish sand the primer no coarser than 600 (or 5oo dry). Most clears will cover 800 grit scratches. You could prep the blend are with 800, or as fine as 1000. I would think that anything finer than 1000 may have adhesion issues. Or you can use a grey or gold scotch brite pad with prep paste. For a beginner I would recomend the paste, because it almost eliminates the possibility of burning through the clear coat when prepping/sanding. If you burn through the clear on a blend panel, base must be applied over that area which defeats the purpose of blending.
[quote=”MoCoke” post=15341][quote=”bobwires” post=15337][quote=”Ben” post=15323]With painting over the old paint and the grey primer, a value-shaded sealer would have helped tremendously.[/quote]
I got a gallon of martin senour sealer a couple years ago when I was starting my first paint job, but it’s pretty dark gray. almost black. Do you have to have some special sealer ‘base’ that you add black tint to to get the right value?[/quote]
you just need a tintable sealer or primer. i think the maximum amount of tint is 10%. they save lots of time and material[/quote]
If they are not tintable, then you usually buy black (dk grey) and white sealer. Then mix them in the proper ratio to get the correct value (shade of grey). Read the tech sheet for the product you are using and it will explain this if it is capable of being used as such.
[quote=”Kevin Campbell” post=15332]Does anybody have access for motorcycle colors. All I can bring up in my Dupont is autos. I’ve got a 2009 Kawasaki Ninja 250 code 17K Metallic Diablo Black. Chromabase code preferred.[/quote]
I used to do a lot of bikes, I found that I could only get formulas now and then (say one in every 5 jobs).
I used the camera to scan them and always had great success getting a bendable match. If you don’t have the camera I am sure your jobber will be glad to help you out.
Good luck!
With painting over the old paint and the grey primer, a value-shaded sealer would have helped tremendously.
One of the reasons cheaper paints are so cheap is because of the cheaper pigments which usually makes for poor coverage. However, if 4 coats of the red was able to hide all that, that really isn’t too bad.
Good job nonetheless. Glad to see you removed most parts before painting, makes for a much better job!
[quote=”dcturcotte” post=15279]Global isn’t the greatest system, that being said it’s far from the worst solvent system out there. Using the appropriate sealer I rarely had a color cover take more then 3 coats to get coverage. In my time using it I found it fairly easy to make it work for me. You got a pretty good deal man, once you have both systems complete you’ll be laughing. Just use your value shade sealers and do some sprayouts (and keep them) to make sure you don’t have to tint.[/quote]
I used Global for a while too and had good success. Colour matches were good and I found it to be a fairly easy system to use.