Thanks Shin. My camera is not great and especially bad for close-ups.
No steam, or kerf cuts - just used about every clamp I own and LOTS of glue (squeezing out of the sides). I left it clamped for a couple days to make certain the glue was dry. I assembled these in December, and no signs of movement.
Thanks for the info John.
Just to get this straight in my head... you sand your MDF to a level that you're happy with, then apply a few coats of the urethane paint as a primer. That's allowed to dry, then is sanded. Yes?
Do you then put on more coats of the same, before applying a lacquer, or do you go straight to the clearcoat?
PS You've done very well to get that result from bending 5/8" MDF with no kerfs. I'm amazed it didn't crack.
Just to get this straight in my head... you sand your MDF to a level that you're happy with, then apply a few coats of the urethane paint as a primer. That's allowed to dry, then is sanded. Yes?
Do you then put on more coats of the same, before applying a lacquer, or do you go straight to the clearcoat?
PS You've done very well to get that result from bending 5/8" MDF with no kerfs. I'm amazed it didn't crack.
sploo said:
The primer coat is sprayed 6 to 8 coats with 15-20 minutes between coats. This builds a thick film. Let dry a few days then repair defects and sand smooth with 320 grit paper.
The paint coat is 8 to 10 sprayed coats, with 15-20 minutes flash time. This produces a layer thick enough for a final finish - sand with 1000 grit wet, then 2000 grit wet. I then poish with fine polishing compound and high speed buff. Then wax with Meguier's car wax.
I don't use a clear finish on paint, especially not a lacquer. Any clear I use is polyuethane.
Its best if you stick with one type of finishing product from first to last, and then you won't run into problems with incompatibility. Example: don't use urethane based paint or clear over shellsc or lacquer.
John - many thanks for the info!
I've cut another set of MDF circles and have glued them together (BTW Rich, I found a local shop that sells Extramite - so no need to post, cheers).
I have three stacks glued with PVA, three epoxy glued, and three Extramite glued.
After sanding, I plan to spray one of each glued types with high solids automotive primer, one of each with urethane paint, and coat one of each with epoxy.
This should test out John's urethane method on the MDF (and weather) we get here in the UK. It should also show if it's the PVA glue, as we know that PVA + epoxy or PVA + high solids results in visible lines.
I'm trying to source the Varathane paint in the UK, but no response from the manufacturer yet. Anyone know of urethane paint products over here?
I've cut another set of MDF circles and have glued them together (BTW Rich, I found a local shop that sells Extramite - so no need to post, cheers).
I have three stacks glued with PVA, three epoxy glued, and three Extramite glued.
After sanding, I plan to spray one of each glued types with high solids automotive primer, one of each with urethane paint, and coat one of each with epoxy.
This should test out John's urethane method on the MDF (and weather) we get here in the UK. It should also show if it's the PVA glue, as we know that PVA + epoxy or PVA + high solids results in visible lines.
I'm trying to source the Varathane paint in the UK, but no response from the manufacturer yet. Anyone know of urethane paint products over here?
No trouble Sploo. Good luck with your test. Remember, lots of dry time for the glue before paint.
Not sure what the weather is like there at this time of the year, but here it's hot and humid - perfect!🙂
Got another couple pics for consideration. Show the final results of my paint process on the curved baffle speakers. Although the speakers are not done entirely, the baffles are.
The pictures are the best I could do (a little grainy) with my ancient 2.1 megapixel camera, but it should be clear enough.
Not sure what the weather is like there at this time of the year, but here it's hot and humid - perfect!🙂
Got another couple pics for consideration. Show the final results of my paint process on the curved baffle speakers. Although the speakers are not done entirely, the baffles are.
The pictures are the best I could do (a little grainy) with my ancient 2.1 megapixel camera, but it should be clear enough.
Attachments
Good news Sploo, can't wait for the results. Thanks for letting me know, I was going to send you the glue tomorrow.
John - the speaker looks great. What drivers are you planning for it?
The blocks have been drying for a couple of days, have now been sanded smooth, and are currently in my house (hopefully acclimatising). The weather here? Well, in the last week it's been cold, wet, warm, wet, and today, very warm, dry and sunny. That's why we Brits talk so much about the weather - we get so much of it. 😉
BTW I've had a response from the UK Rustoleum representative, and unfortunately: "this product hasn't been registered nor stocked in the EU".
Do you know of any other suitable brands, and I'll try to see if I can get them here?
The blocks have been drying for a couple of days, have now been sanded smooth, and are currently in my house (hopefully acclimatising). The weather here? Well, in the last week it's been cold, wet, warm, wet, and today, very warm, dry and sunny. That's why we Brits talk so much about the weather - we get so much of it. 😉
BTW I've had a response from the UK Rustoleum representative, and unfortunately: "this product hasn't been registered nor stocked in the EU".
Do you know of any other suitable brands, and I'll try to see if I can get them here?
sploo said:
Any high quality alkyd high gloss paint will be almost as good, given the edge grain of the MDF (or the whole piece) is "primed" with polyurethane first.
The following links are products in the UK that look to me to be similar to the stuff I use:
Clear polyurethane:
http://www.rustins.co.uk/product.htm?chgprod=POVC
Gloss alkyd paint:
http://www.rustins.co.uk/product.htm?chgprod=BLAG
The gloss black will go on the same way as the Varathane pant, and has similar properties.
As for the speakers, thanks. The drivers (I have them already) are:
Woofer - Seas CA21REX(H333)
Midrange - Max Fidelity pro411m8
Tweeter - Scanspeak D2905/9300.
All have +90 db sensitivity and very smooth response.
Will be driven all active, I'm working on the filters and amps now. It's more fun than any one person should be allowed to have.
🙂
MJL21193 said:
Excellent info John, thanks.
It's just occurred to me that I already have some clear polyurethane varnish in the garage! I never thought of using that to seal the MDF.
So... if I put on a few coats of the varnish, let it dry, and sand it flat, could I put cellulose over the top, or is the point that I need a urethane or alkyd paint?
The reason I'm asking is that I'm using cellulose at the moment, and can get it in multiple colours.
MJL21193 said:
Sounds great. I'm not familiar with the ScanSpeak 9300, but I've used the 9500 and love the sound it gives.
Probably getting a bit off topic here, but what route are you going for the active xover and amps (DCX2496 + off-the-shelf amps, or all DIY)?
sploo said:
Hi Sploo,
If the varnish that you have is indeed solvent based polyurethane, that's fine to prime with. Just thin enough for spraying.
As for cellulose, what is the finish exactly? If it's nitrocellulose lacquer, then it's safe to apply over cured urethane (though you can't put urethane over lacquer).
With that said, a good part of my success with the finish is due to the elasticity of the finish and the thick film build. Urethane and alkyd finishes dry by solvent evaporation and cure by cross linking the polymers with the absorption of oxygen from the air . This forms a finish that is impervious to most solvents.
Lacquer dries by evaporation only, and can be dissolved by it's own solvent. It is more brittle.
Bottom line is that I can't say if lacquer will give the same results.
For what it's worth, if I were to change the paint I'm using, I'd step up to a full 2 part automotive paint - Acrylic urethane enamel, the toughest and most durable paint to date. Comes in clear also. (Hey, it's what Wilson Audio uses 🙂 )
sploo said:
I'm DIY to the core, so everything homemade (even the circuit boards). Two 3-way active filters based on Rod Elliot's 24dB/octave P09 (one is finished and tested).
Amps will be four LM3886 based for the mids and tweeters. I have two discrete 100 watt amps built for the woofers (a little extra headroom). Six slide pots for level controll and six LED VU meters for a good light show.
A huge undertaking, but I'm sure it will be worth it.
I can tell you what not to use, I bought this Cr*p "DAP Water Putty Wood Patch by Plastic Wood" I assumed that it was the powdered wood putty that I used to buy, it isn't. If I had to guess I'd say it is powdered sheetrock mud.
I am way ticked off about this stuff. You put it on, it dries pretty quickly, but it has the strength of sheetrock mud, and sands just like it, big billowing clouds of white dust, and when you're done there's nothing left.
Does anyone know precisely what the old water putty, powdered wood putty is called, so that "I don't get fooled again?"
Paul
I am way ticked off about this stuff. You put it on, it dries pretty quickly, but it has the strength of sheetrock mud, and sands just like it, big billowing clouds of white dust, and when you're done there's nothing left.
Does anyone know precisely what the old water putty, powdered wood putty is called, so that "I don't get fooled again?"
Paul
John,
I'm sure it's a poly varnish. Cleanup is with white spirit IRC. Will check tonight.
The method I've been using for painting is: prime (with one of 2K automotive high solids primer, epoxy, etc. etc.), sand flat, paint with a few coats of cellulose, sand flat, paint with a few coats of clear coat.
The clear coat I've been using is single pack acrylic, and the base coat paint is cellulose - both for the simple reason that I can buy them!
I could move to an acrylic base, and I'd love to use 2 pack clear coat, but I do try to stay away from the 2K stuff as I don't have the right airfed breathing gear.
Amp/filter stuff sounds great BTW.
I'm sure it's a poly varnish. Cleanup is with white spirit IRC. Will check tonight.
The method I've been using for painting is: prime (with one of 2K automotive high solids primer, epoxy, etc. etc.), sand flat, paint with a few coats of cellulose, sand flat, paint with a few coats of clear coat.
The clear coat I've been using is single pack acrylic, and the base coat paint is cellulose - both for the simple reason that I can buy them!
I could move to an acrylic base, and I'd love to use 2 pack clear coat, but I do try to stay away from the 2K stuff as I don't have the right airfed breathing gear.
Amp/filter stuff sounds great BTW.
Quick update: The varnish is indeed a solvent based poly (http://www.screwfix.com/app/sfd/cat/pro.jsp?id=29196&ts=88635#)
I've put a couple of coats of the varnish on three of the blocks, and a first coat of epoxy on three more. I ran out of time tonight, but tomorrow I hope to use the 2K primer on the final three, and do some extra varnish and epoxy coats.
More in the next stunningly interesting instalment...
I've put a couple of coats of the varnish on three of the blocks, and a first coat of epoxy on three more. I ran out of time tonight, but tomorrow I hope to use the 2K primer on the final three, and do some extra varnish and epoxy coats.
More in the next stunningly interesting instalment...
what is a good wood protector as in for painted items to stop it being easy scratched or just general damage
i did try a spray thing Lacquer type i think but even with few coats still gets marks on it
i did try a spray thing Lacquer type i think but even with few coats still gets marks on it
larksp said:
You need something that dries very hard. Ironically, the polyurethane varnish I was just writing about seems to protect pretty well.
The toughest stuff I've had experience with is 2 part automotive lacquer. However, you will still be able to scratch it with something sufficiently sharp, and it's dangerous stuff to spray.
ok how would be the best way of putting in on then
something like a roller and what about thinning it and few coats seems to get less marks with thiner coats on or does it go on well with out brush marks anyway
something like a roller and what about thinning it and few coats seems to get less marks with thiner coats on or does it go on well with out brush marks anyway
aceinc said:
Sorry didn't quote aceinc in my earlier post. You may be looking for Durham's Rock Hard Water Putty. Awesome stuff. www.waterputty.com
Mike
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