Opaque lacquer finish
Concerns about the substrate used and avoiding orangle peel are addressed. March 4, 2002
Question
We have a job to do in opaque lacquer - white with about a 30 degree gloss. Typically, this type of finish shows every defect. We normally use MDF for the substrate, with about three coats of primer, a topcoat and then clear water white over that. Any experience using a factory filled board? Any other suggestions to arrive at a perfect finish?
Forum Responses
You should be able to accomplish a full fill, blemish-free finish on "good" MDF in 3 steps (provided you take the time to sand properly): primer, primer, topcoat.
As far as pigmented systems go, I have found Becker Acroma to be the best, with Chemcraft a close second.
30 degree sheen is not that shiny. It would not show defects as easy as an 80 or 90 degree. I think that satin is around 35 or 40 degree, so 30 should be even less than satin. The above is correct. With two coats of a good primer, it may even take two topcoats to get what you want, but the primer is the secret, cause what you see on primer is what you get on topcoat.
Good prep on the primer and two coats of lacquer should do it as a standard approach. Some flow out additive may be advised to avoid orange peel. 90 degree gloss is a high gloss finish. Patience, discipline and a desire to create a quality product.
From contributor J:
My advice: sand thoroughly 150/180, don't polish - smoother is not always better.
1) Spray first coat of your primer on ends and places the MDF has been opened, allow to dry, scuff well 220/360. High solids primers perform best.
2) Apply two coats of your primer wet on wet. When dry, scuff thoroughly 220.
3) Using a quality paint do a box coat. A clear coat is really not necessary unless you are distressing or using a glazed colorant.
From the original questioner:
Anyone have experience with factory filled material? Another problem we still have is a slight orange peel. Any suggestions as to how to eliminate this? Does the high solids white topcoat affect this?
From contributor J:
Flow additive/thinner would help. Spray equipment plays an important part in this as well. Not quite sure what you mean by factory filled - are you referring to polyester or two part urethane?
From the original questioner:
Factory filled refers to particle board or MDF which has been primed or filled at factory on a flat line which applies a paint type product that fills all defects and then is flat line machine sanded to about 180. This usually is as smooth as a baby's posterior but sometimes it is too smooth for the next coat to adhere.
From contributor J:
You purchase your board pre-primed, I take it. The manufacturer most likely uses a UV cure primer. What is their recommendation for topcoating? I've had excellent results painting MDF over the years using ML Campbell's pigmented system Clawlock primer followed by their Resistant topcoat. Along with Kremlin spray equipment, with factory looking results (thermafoil). Also, 180 gr is not too smooth for a topcoat - it's actually too coarse.
Factory filled products are manufactured in a production atmosphere, with a lot of automated machines. This allows the speed they need to mass-produce pre-primed materials. These materials could sit on the shelf at their facility for awhile before orders are placed, filled and shipped out to the end user. This will give the primer time to settle down. If you scuff sand the primer already on the particleboard or MDF with 320 grit paper, then spray a good finish coat, you might see better results. I know some shops who use the factory filled products that will do a scuff sand and still do a light primer coat of their own before finishing. When spraying at your shop, you would normally sand in between each coat so you get good adhesion. I know you want to save time by ordering pre-primed, but until you get a method down that works good for you, do some test pieces to see how things work out.
As for orange peel, check to make sure you are thinning the paint properly, the air pressures and fluid pressures are set correctly and that you are spraying good wet coats. With higher solid paints, also check the air cap, needle and nozzles you use on your spray gun - make sure they are the correct ones for your paint products.
Lisa Gilbert, forum technical advisor
The biggest keys I see are very good lighting and a low angle! This will show defects in the first primer coat that can be sanded and puttied before the second coat of primer. On MDF, I like to use glue sizing wet sanded into any milled areas before the 1st coat of primer. I also like to sand the MDF to make sure it's flat before priming. The good lighting will help here also. On these finishes, like most, 90% of the job is in the prep work.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor N:
I have sprayed MDF cabinets for years with very little problems, using both high gloss and semi. The trick in in the prime coats. Get the primer correct and a good top quality finish coat will look fine. I usually prime two coats, sanding with 180 first coat and with 220 second coat. Wait 24 hours, apply finish coat, wait one hour for flash and apply second coat if needed. Mirror like results, usually. If you get any orange peel, sand with 1200 wet-dry then 1500 and buff out.
Comment from contributor C:
I just painted a really beat up Yamaha baby grand piano and thanks to this forum, I finally got going in the right direction. About 25 years ago, I used to build custom cabinets and spray them with several coats of really good satin lacquer with my Binks 69 siphon gun. My Binks is so old it doesn't work any more, so I bought a new Anest Iwatta lph400 hvlp gun. I had two problems I did not know how to adjust the gun properly and the only lacquer I could get was junk. The sanding sealer was gummy and the top coat was even worse. I got introduced to polyester here and I tried contacting that GVI supply company that is often mentioned here, but the contact was out of town. I bought the polyester primer and urethane one coat at a local automotive paint dealer. I also got a cheap 2.0 primer gun there. It generally went very well. I used 220 paper to cut the primer down quickly and I sanded up to 400. The worst problem I had was that poor light and black lacquer is a bad combination. I got some runs and I backed into the piano once (**!!##). I sprayed over it and I'll try to sand and buff it out. Thanks for all the great advice.
