Amateur Build of the X-MTM Encore

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jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #120 on: 28 Jul 2020, 01:10 am »
Cross over build reference:
https://youtu.be/rIxig_9i-Iw

Danny does a nice job with showing how to assemble a crossover.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #121 on: 1 Aug 2020, 12:58 pm »
A set back... :(

A while back I noticed some oily spots on the MDF and passed it off as maybe being something that was there from the store...  Recently, however, I found a big splotch on the outside of the front panel that wasn’t there when I routed it, so I knew it was something of my doing...  And a quick search on my work table turned up an old oil spill on my work bench that pretty well blended in and I didn’t see it until I was actually looking for it.  Ugh  :shake:

I can’t believe how well the MDF sucked that stuff up.  It is like a sponge.  Of course, my concern is for later on when I go to put the finish on.  I plan a painted finish, so staining isn’t an issue.  I just need to make sure the finish/paint sticks.

So now comes the process of cleaning it out of the panels.  Right now I have tried paint thinner and paper towels, which seems to have removed some of it.  After I do that a few times, I plan to wipe it down with some alcohol.  I would rather go this route than have to go get another sheet of MDF and cut new panels.

Any suggestions out there as to getting rid of this mess?  Or am I on the right path with the paint thinner?

Abby356

Re: Amateur Build of the X-MTM Encore
« Reply #122 on: 1 Aug 2020, 02:05 pm »
If you intend to paint the baffles, I would use the classic BIN shellac base primer.

Which is what i used when prepping these early E. Geddes kits for professional paint with House of Kolor automotive paint. BIN is a great all around sealer for MDF to prevent MDF from soaking up humidity or moisture later (paint inside of box/enclosure too), and sands incredibly smooth.




Peter J

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Re: Amateur Build of the X-MTM Encore
« Reply #123 on: 1 Aug 2020, 02:11 pm »
Bummer. First thing to determine is what the nature of the oil is. Most oil is petroleum based, so alcohol won't be a solvent for it, but paint thinner (mineral spirits) probably would be.

You could make a poultice of sorts with a tight wad of cloth or paper towel lightly dampened with solvent (paint thinner) and set on surface for a bit. The glue in MDF won't be affected in a short exposure, but off the cuff, I think I'd limit to perhaps an hour.  Rubbing actually isn't very effective as it just tends to suspend the oil and move it around.

When it comes time to paint, a stain blocking primer or dewaxed shellac might be a good first coat as it will help to seal whatever residue remains and keep if from affecting subsequent topcoats. At least some prep will depend on what you intend to finish with. Solvent or oil base will be less affected than water base in my experience.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #124 on: 1 Aug 2020, 02:56 pm »
Bummer!  Good word for it.

I thought about using shellac as an undercoat.  Thanks for the advice on the primer/sealer version.  I have used plain shellac as a finish coat before.  I am not sure if it is de-waxed though, I would just get the primer version.

It didn’t take me long to remember remember the oil spill from a long time ago.  The smell is a dead give-away... 90w gear oil.  The smell of that stuff is memorable.

Also good advice on making a poultice (I wonder how many people are familiar with that word... :lol:).  I had already thought of just putting some “speedy dry” (basically clay cat litter) on it and let it sit.  But soaking it with paint thinner first and then doing that might work.  It seems that would draw it out better.

I did soak it with paint thinner and then blotted it.  This worked to some extent.  But I didn’t soak it for very long as I was afraid of the paint thinner drawing the oil further into the MDF. 

So, I will continue on with this advice and will let you know how well I do.

Thanks for posting back with the suggestions...

BTW - I really like the teal colored speakers - nice job on them.   :thumb:

mlundy57

Re: Amateur Build of the X-MTM Encore
« Reply #125 on: 1 Aug 2020, 03:15 pm »
Listen to Peter  :thumb:

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #126 on: 1 Aug 2020, 03:57 pm »
 :bowdown:

 :lol:

Already working on it...

AlexH

Re: Amateur Build of the X-MTM Encore
« Reply #127 on: 1 Aug 2020, 07:35 pm »
If you intend to paint the baffles, I would use the classic BIN shellac base primer.

Which is what i used when prepping these early E. Geddes kits for professional paint with House of Kolor automotive paint. BIN is a great all around sealer for MDF to prevent MDF from soaking up humidity or moisture later (paint inside of box/enclosure too), and sands incredibly smooth.


BIN primer is a good idea as well. BIN is just a white pigmented shellac.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #128 on: 1 Aug 2020, 08:10 pm »
I was at my local hardware store earlier today after the suggestion was made and found the BIN shellac primer...

Thanks for the advice and endorsement.  Even before this happened I was wondering about whether this should be primed on the outside, at least, before painting it.  I guess that is a given now...  :roll:

Right now the front panel has been wet down with mineral spirits and has several layers of paper towel and a scrap piece of MDF over that, and all of that is being compress under about 50# of weight.  The speedy-dry didn’t do much from what I could tell.  There didn’t seem to be enough surface area contact to draw the oil out.  This stuff is more for a pool of a liquid than my current need.

hawkeyejw

Re: Amateur Build of the X-MTM Encore
« Reply #129 on: 1 Aug 2020, 09:42 pm »
Definitely prime and sand MDF before your top coat. It will soak up a lot and be inconsistent otherwise.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #130 on: 1 Aug 2020, 09:53 pm »
Does the BIN shellac primer sand the same or similarly to ordinary shellac.  Or does the white pigment cause it to be gummy?

Peter J

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Re: Amateur Build of the X-MTM Encore
« Reply #131 on: 1 Aug 2020, 10:05 pm »
The BIN will sand OK and is a good barrier coat. For best sanding, I've found Cover Stain, also made by Zinnser to powder when sanding and build a little more. This is for oil based stuff. I think the water base can be in spray cans too, but I'm not as fond of it. Cover Stain is best if left to dry overnight. BIN will be faster.

AlexH

Re: Amateur Build of the X-MTM Encore
« Reply #132 on: 1 Aug 2020, 11:12 pm »
Yeah, Cover Stain is good stuff. Most of Zinsser's stuff is good. They make my favorite varnish Quick Satin 15. I cringed when they were bought by Rustoleum.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #133 on: 5 Aug 2020, 08:30 pm »
Just a quick update to say that I think I have solved the oil in the MDF issue...  Baby powder...  Actually, cornstarch, which is the main ingredient of baby powder these days.

I soaked the oily area down with paint thinner, let it sit for a minute or two (not long at all).  Then I put a layer of baby powder over that.  The cornstarch dries the MDF and appears to pull the oil out with the paint thinner.  I had the MDF on top of some paper so I could scrape the power off the MDF and onto the paper.  This was then easy to ball up and throw away,  and I wasn’t clogging up the shop vac filter with the powder.

Success!  :green:

I also made 2 more of my 3rd hand clamps, this time using the MilesCraft clamps.  The hole size for these is 21/64 inch, as compared to the others which is 15/16 inch.  The only thing about the MilesCraft clamps is that they are a bit heavier than the other 2 clamps I made, but nothing like the other corner clamps I bought.  These should be good and really handy for dry fitup: