Spraying MDF

[paulhayes]

I intend spaying 4 MDF 18mm thick panels circa 0.7m2 each. I have had cut to size B&Q MDF so likley not MR MDF. I have a new electric Wagner W70 spray gun never used but 10 yrs old, but only 40 watts.

I intend spraying a couple of good primer sealer coats like Morells, and then with several top coats, and a lacquer, rubbing down with progressive grit paper between each coat to get a good high gloss finish. I have never used the Wagner before. Does anyone know what result I'm likely to get from a cheap spray gun like this, would I be wasting my time in even trying toachieve the result I would like?

 

[promhandicam]

If you gave the gun and the materials then try it! What have you got to loose? The only issue would probably be having to thin the paint to get it to atomise. Morrells wb orimrr and laquer are both gun ready and so if you thin them more than about 5 % you may have problems. Your biggest issue might be finding somewhere warm enough - I've been trying to spray wb primer today and it's a bloody nightmare.

 

[Tusses]

have a practice on some cheap hardboard 1st

Practice is worth it's time, over and over !

See how the gun performs, maybe try thinning the paint a bit and spraying some more till you get the best results

Rich

 

[mailee]

Not trying to wee on your bonfire but i wouldn't think you will get very good results with the Wagner. (I assume it is an electric diaphragm gun and not air powered) I will be surprised if the gun will atomise the Morrells enough as it needs to be pretty thin for the Wagner. also as has been stated it is pretty cold for spraying anything at the moment and cold and damp can cause lots of problems. JMHO. :wink:

 

[paulhayes]

Thanks guys, the Wagner is an electric diaphram type. I'll give it a go and see what results I can achieve. I was hoping to use water based acrylic primer sealer, with matching top coat and lacquer I hope for its fast drying capability and ease of cleaning. What minimum air-temp does one need to spray using acrylic paint?
Morrells has been a brand generally recommended for acrylic, perhaps there are others I should consider? I guess I only need 1/2 ltr of each, no idea at the moment where to buy in Bucks or on-line?

If the pressure from this gun is too weak, even when diluting the paint, I will have to look at something like the Earlex Pro HV5000, which I assume would be fine for the amount of work I intend using it for, are there others I should consider?
Paul

 

[promhandicam]

Minimum quantity of Morrells lacquers is 5 litres - just bought some primer and 20% white wb topcoat and it was around £100 delivered. Re. the Earlex - yes it will be fine with a 1.5mm or 2.0mm needle depending on the area you are wanting to cover. If you decide to go for the Earlex try giving them a call - they are based in Guildford - as they sometimes have customer returns for sale at very good prices.

 

[paulhayes]

I have abandoned the idea of using WB paint. Morrells min quantity is too much.

I can buy locally cellulose based paint by the 0.5 ltr and use a friend's spray gun and compressor. I want to spray a new IKEA kitchen unit painted door and some 28mm thick standard mdf. I would like to achieve a high gloss finish and have been informed cellulose will achieve this. Some sites have suggested a Spackling filler to seal the edges of the MDF, I can't buy this locally. Can I just use a cellulose filler primer to do this, or will I require another type of sealer?

Will a cellulose primer and paint be compatible with the IKEA paint type unknown?

The minimium amount of primer I can buy is 1ltr, are 0.50 ltr amounts available generally.

Thanks

 

[mailee]

Yes you can use a cellulose primer/filler to spray the MDF but it is doesn't have the high build that the Morrells does. It will fill the edges of the MDF but will take a few coats. I used to use it before I discovered the Morrells stuff. You will probably find a lot more sinkage with it. With the standard 'fluffy' MDF I have found even using the Morrells primer sealer it will take three coats to seal the edges. I know the Morrells is only available in 5 ltr quantities but it is aimed at trade after all. If you buy the 2K it does keep a long time on the shelf so can be used for future jobs. :wink:
PS. I am not sure if it will be compatible with the Ikea paint, as it is cellulose based it could react, best to try a small section that is hidden first.

 

[paulhayes]

Thanks for the advice. The car auto industry now uses 2K paint which is WB, I had thought this was highly toxic, but I think I'm confusing this with another 2K type containing arsenic. I assume cellulose based paints will generally dry quicker than WB based? Using cellulose I had hoped to allow say a 10-15 mins drying time between each per coat. I assume I can then using progressive grit papers, flatten the paint after say each 3 application coats?

I don't mind building up the primer base coat with say 5 coats if takes about an hour. I'm trying to make the whole process easier for myself by choosing a cellulose based paint which will cover the IKEA door, and isn't too dependant on air temp.

 

[paulhayes]

Due to other work, this project has been on hold. I have managed to borrow an electric 50ltr compressor with an air-gun/paint container. I have spoken with my local car body workshop who have recommended using 2 Pack acrylic paint with an inbuilt lacquer to achieve a high gloss finish on my MDF panels approx. single surface area =2M2. They have suggested the following method:-

Primer 3 coats (etch based to seal), 320 grit and then 600 grit to flatten the 3rd coat only, with circa 5 mins drying time between each coat.
Top coat 1 coat only flattened using a wet pad of wet & dry 1500 grit lightly.
When top coat fully dry a body cut compound applied to polish out all scratches and then buffed to achieve a high gloss finish. Guess I'll need a pad cushion to fit to cordless drill to buff-up.

I'm not sure on what air pressure I need to set the compressor to using 2 pack paint, and primer?

Does this sound a plausible option to pursue? They also reckon I will need 1 litre of primer and 0.5 ltr for the top coat.
Air temp inside garage is likely to be warm for spraying at circa 75/80F.

I will practise on some spare off-cuts of MDF, but any comments appreciated.

 

[mailee]

That sounds about right to me. Just be sure there is enough top coat on as the pad will remove the paint quickly when you start to polish it. As for the air pressure it should be in the region of 30 to 40 PSI but test it on a scrap piece first. Start with a low pressure and gradually raise it until the paint atomises correctly. HTH.

 

[paulhayes]

Thanks I will practise and gently increase the air pressure. If I played safe and planned to apply 2 top coats, would I then need to flatten down very carefully the first top coat, before applying the second top coat, or could I just build-up a reasonable thickness with 2nd coat to flatten down in one go?

 

[mailee]

It really depends on how the first coat goes on. I would recommend flatting down the first coat though as there will no doubt be some dust in the finish. HTH. :wink:

 

[paulhayes]

I don't have an air-fed respirator mask, just a Drager paint filter respirator mask. This leaves me uneasy with isocyanate in 2 Pack car paints. It leaves Morrells as the only solution, but they only sell trade 5ltrs quantities, which for 2m2 is too much for this project.

Zinsser 123 would seem fine to prime the MDF, the IKEA kitchen door (new) it might be cellulose sprayed, but I guess I could rub down and try with the 123. Zinsser bin ideal but shellac and a devil to remove from air gun so will avoid.

What WB top coats ideally for a gloss finish could I use as a good alternative to spray? None of the Dulux, Farrow & Ball, Crown i.e main manufacturers state their paints can be sprayed. The WB chemical composition can't be that different to Morrells, or can it? I had selected an F&B colour, but am flexible as to an alternative near enough colour. The Ronseal Diamond gloss recommended is only available in white.

I guess it is guys like you in the trade who have experimented and therefore have actual experience of the results, which I can only use to base my choice. Shame as Morrells have a local unit near me.

 

[paulhayes]

I'm having real problems getting Zinsser 123 WB primer to atomise from the gun...have diluted 10% with water using 60-80 PSI pressure, have gone through all option/combinations of air flow and needle jet adjustments, a thoroughly clean gun and container...what I'm doing wrong? Plenty of air pressure but no paint.

Does the primer need thinning beyond 10%? Zinsser say 10% max dilution with water.

 

[mailee]

Sorry Paul, but i can't help with the water based Zinnser as I have never used it. However if you have tried it with an air pressure of up to 60 - 70 PSI then I would think there is something wrong with the spray gun! Have you tried just spraying thinner through it first? At those pressures you could almost spray underseal! :shock:

 

[paulhayes]

Thanks, could be the gun, as I release the trigger there is some after or delayed spray very odd. Think I'll have to ditch gun/compressor return to my friend and buy a HVLP set-up. There are numerous Earlex models, the one favoured on the site seems to be the Pro HV5000, I assume the more you pay the larger the motor, I need a pressure of 2300-2700 for my Farrow & Ball top coat WB gloss paint.

 

[paulhayes]

I have read mixed reviews via Screwfix's customer feed-back on their web-site for the HVLP Erbauer spay gun, it's their own brand. I gave-up halfway through my project as the compressor had a fault. I have bought some water based Farrow & Ball gloss finish paint, which they recommend using an HVLP gun to apply.

Has anyone used the HVLP Erbauer spray gun? Would be good enough to spray my Zinser B primed MDF cupboard doors?

 

[Mooeee]

Paul

HVLP is the way to go, look on ebay for a used sprayer, I bought the Fuji Q4 which has done me proud, its a great system easy to use and easy to clean, I had never done any spraying but managed to spray the kitchen cabinets that I made, inside the cabinets I sprayed Morrells Pre-catalyst Lacquer and for the face frames and doors I sprayed Dulux water based eggshell.

Cheers

Mooeee

 

[kfenelon]

Remember what ever finish you are going to use place the container in a bowl of hot water for 10 minuet's to warm up the product it will flow much better