Paint question on flex agent

I

imported_Auto Concierge

New member
Not sure where to post this, but I'm guessing that at least a number of you on here have done your own painting in addition to detailing. I'm venturing into the world of amateur painting and have what I think is a simple question - what is a good ratio for flex agent? The paint that I have claims it is not needed, but I am painting a dirt bike and the front fender is Very flexy. And I believe that it can't hurt to add some flex. So what is a good ratio? 1:1? 10:1? Anyone have a ballpark idea?
 
I'd follow the mfgr's recommendations if the paint you're using is meant for plastics. Make sure you use a plastic adhesion promoter if required. If the paint in thin enough, then it should be able to flex some without cracking. The thicker the coating, the more susceptible it will be to cracking. For the off road race bikes I end up painting, I simply use Krylon Fusion (meant for plastics / no primer required) and have had excellent results straight from the rattle can. If the fenders or panels are badly scratched, I’ll first sand most or all of the scratches out, but often times the scratches are very deep and I probably only remove 80% of the defects this way. I also wipe the fenders down with Acetone before painting them. Painting plastic fuel tanks is a problem due to out-gassing, but the fenders and panels can be painted with good results. For the Baja race bikes, I paint their front fenders black to minimize glare from their lights and sometimes I paint all the fenders, shrouds and panels, but never the fuel tank. The bikes get beat to heck, crashed, run through scrub, Cholla, etc, but the Krylon fusion holds up pretty darn well. And when they get scratched up too badly, I simply sand them down and give them a fresh coat. You can find Krylon Fusion as Wally World for $5 a can in many colors.



If I was restoring something super rare and or very special that I wasn’t going to ride much and wanted a show bike finish, then I wouldn’t be shooting from the rattle can, but plenty of off road bikers have given me nothing but positive comments about my work from the Krylon Fusion rattle can.



If you’re working with the original colored plastic, you can finish it out very nicely by sanding it down in steps. Once it’s sanded down enough, then wipe on some acrylic floor polish and let it dry. Any floor polish from the grocery store that contains acrylics will usually do the trick. You can apply several coats of acrylic floor polish if you wish, but let it dry between each coat (it acts like a clear coat). Then buff it with extra fine 00 steel wool and again with 000 super fine steel wool and you can follow that up with your d/a and some polish to make it look even nicer. People are always amazed with the looks of their bike when I’m done with it from using this process.
 
I'd try to see if there is a Krylon Fusion color that will work for you. Dirt bike plastic is notorious for shedding any paint put on it no matter what the prep. I'm assuming you are restoring something. Otherwise replacement plastics for dirtbikes are rediciously cheap for a complete set. Well ridiciously compared to sportbike plastics.
 
Thanks for your experienced reply, Gadson. I've read that dirt bike plastics are not receptive to paint, their properties that make them good for flexing and keeping dirt from sticking, are also the properties that don't like paint. But apparently for you it is possible. And the guy I bought this bike from did a rattle can job and it looked horrible, but it stayed put. Som I'm not very worried about it.



Two reasons I didn't want to go with Krylon - I wanted a very specific color and I wanted to try to do a good job with "real" paint. :) I'd like to get better at this. And I already bought the paint, so buying more is not an option!
 
A flex additive shouldn't be used when the paint manufactuer say's it isnt required. Alot of paints today that are part of a a BC/CC (Base and Clear Coat) system are that way.



Clear Coats are another story, they will range from not needed, use for optimum performance, and required.



The product being used will state the ratio's when the Flex Additive is a suitable component.



I do autobody re-finishing as another hobby but run with a pro setup (Guns, air compressor, what have you) I've never painted bikes but for anything long lasting with professional results rattle cans aren't an option.



If your interested to learn more about painting you can head over to the forums at The Autobody Store. It's run by an owner of Body Shop who's been in the buisness since the 60's and alot of pro's as well as first time novice painters hang there.





MorBiD
 
Morbid, thanks for the link. This is a single stage acrylic enamel, I didn't buy the BC/CC two stage product. Didn't want to get that difficult for my first time. I just don't trust the stock paint for accepting the amount of flex from the front fender. I mean, you can take that thing and bend it practically 180 degrees. From what I've read (in a book on plastic repair, not just on the interweb!), it doesn't hurt to add flex agent, so why not do it?
 
The reason for not adding a Flex Additive if you don't know if it's a compatiable is this.



When doing a re-finishing job (like your doing) and using 2 part (or 2K) component paints (as oppose to the 1 part or 1K rattle can stuff) there are a plether or things than can affect the out come of the finish.



Some can be sanded out and some will require the paint to be removed and you'll have to start all over again. That's another subject and we'll leave that alone for now.



What can happen if you add something to the paint that is not supposed to be there or add something without using the proper ratio's is it won't "lay" right, won't cure, can wrinkle or lift. To name a few.



I will admit that any paint (Single Stage or Base and Clear) that will be used on Flexible Pastic Parts must move with the part.



I've read here and on other forums where people say that the Flex Additive is only to keep the paint from cracking while reassembling the part to the body but I know from talking to the tech's at Dupont that this isn't the case. The Flex Additive will permenately soften the paint/clear.



The word from the horse's mouth is always the one I run with. You should be able to look up the Manufactuer and brand name of the paint your using on the net.



All modern 2k paints have what we call a "P-Sheet" or Product Sheet. These are simply a listing from the folks who made the paint to tell the paint techician what ratio's of what to mix the paint with, the required gun setup and air pressure needed to apply the paint, how long till it's dry and how to dry it (forced air, infared, or air) and how to finish it out.



I would look that up first then go from there. As with anything else there are more ways for things to go wrong than right. With painting you always want to start with as much information as possible about the products you'll be using.



This saves time and money in the long run.



PS



BC/CC is far easier to apply and finish out the Acrylic Enamel or any SS paint when being used with a gun and air compressor. It's more forgiving.



MorBid
 
Ok. Well I'm learning, and I'm going to practice on a single piece with small amounts of paint first. If it doesn't work, then it doesn't work. I did find the data sheet for the paint, and I'll use it as a guideline for doing my practice.
 
Triumph said:
Ok. Well I'm learning, and I'm going to practice on a single piece with small amounts of paint first. If it doesn't work, then it doesn't work. I did find the data sheet for the paint, and I'll use it as a guideline for doing my practice.
Click to expand...



Nothing wrong on either count. If I may, what is the name of the paint your going with and who makes it?
 
Valspar SunCryl 325. Getting this paint was a comedy of errors, I originally wanted PPG paint, they couldn't find the right code, they found the code for Kawasaki Green from Valspar but no PPG equivalent, once it was mixed it was waaay off from what I wanted, they spent a half hour further lightening it with yellow and white, and here I am.



I did one piece, and learned alot about the mechanics of doing this. The paint looks alright, has some orange peel, I guess that means that I didn't reduce it properly. But by doing small scale I couldn't measure the ratios effectively. And the paint says 10-15% reducer, and if you want hardener, to mix that 8:1. But is that 8:1 after adding 10% reducer or beforehand? :nixweiss
 
Any ratio (as in this case 8:1) means parts per base product-part additive. The other additives or reducers are not taken into account.



So you would use 8 parts paint:1 part hardener. When given measurements in percents (%) again you go by how much base product (paint in this case) your mixing at the time.



So .10 x 16oz = 1.6 oz. You can buy special mixing cups at any autobody supply store that will already have the measurements on them (1:1, 2:1,3:1, 4:1, 10%, etc) makes life a whole lot easier than trying to eyeball it. You just decide what ration your going to work with and the lines for that amount are stagger up the cup. They come in small, medium, and large sizes.



OP (Orange Peel) isn't cause so much from the wrong mix if additives per se. More from not using the right reducer for the ambient air temperature in which your shooting the paint. Among other things. I as with many pro's (which I'm not) don't mind a little peel as it can be sanded out later. It's much more peferable than other issues that are much harder to fix.



See here for an index of common issues painters encounter, thier cause and how to effect the repair.
 
K, with minimal difficulty I found the Paint Manufactuer's site for the Valspar SunCryl 325 paint your using. The P sheet can be downloaded from here or from the link to your product.



You should be working from this sheet and not anything else. Except for the gun setup where I prefer to use my gun's manufactuer's reccommendation on settings.



That sheet answers your original question about the Flex Additive/Agent with N/A.



MorBiD
 
You must log in or register to reply here.
Back
Top