Thinning Sarco Type M

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MJ1987
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Thinning Sarco Type M

Post by MJ1987 »

Hi all,

As I continue to restore my windows, I'm always looking for ways to make things simpler and faster. My patience is at an all-time high, so I'm certainly not looking to compromise quality, just to work 'smarter and not harder', as they say. I was watching a tutorial on The Craftsman Blog that shows the creation of storm windows. One of the things he shows pertains to glazing. Rather than using a putty knife to apply the initial bedding, he advocates for "thinning down" your glaze (he uses Sarco Type M) with raw linseed oil. He then puts it into a refillable caulking gun and squeezes it into the rabbet. Last night I tried it with a grout bag, since I didn't have access to a refillable caulking tube. [Side note: tubes cost about $5 each on Amazon and grout bags about $4 at home depot]. The application does make it a lot easier to apply, but thinning it down makes it a bit looser so it squeezes out more easily, especially onto the inside of my window. The Craftsman Blog suggests thinning with raw linseed oil, but I used BLO. My understanding is just that the drying time is faster with the BLO. hopefully this doesn't create any issues; I don't think it will. Just wanted to get some feedback from those here, if this has ever come up.
Matt


I built a chimney for a comrade old;
I did the service not for hope or hire:
And then I travelled on in winter’s cold,
Yet all the day I glowed before the fire.


-Edwin Markham

heartwood
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Re: Thinning Sarco Type M

Post by heartwood »

if it ain't broke, stay the heck away from it!

I have a small heat box where I heat up and soften the putty for bedding...once heated, it is easier to 'mix' the putty by rolling in one's hands and blend the few ingredients and the glass tends to set more evenly...I would not encourage using raw linseed oil as it is very slow drying...even if one cleans the glass and wood surfaces well, the raw oil may interfere with finish paint adhesion (especially water based paints)...the blog author is fairly new to window restoration...

when getting set up to glaze, I have a small squirt bottle of BLO handy...the deeper into the bucket you dig, the drier you will find the putty...spread out a good sized ball of putty, squirt BLO, roll and knead until the consistency is proper...
putty can be hearted in a microwave too...please don't invite me over for dinner though!

...jade

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MJ1987
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Re: Thinning Sarco Type M

Post by MJ1987 »

heartwood wrote:if it ain't broke, stay the heck away from it!

I have a small heat box where I heat up and soften the putty for bedding...once heated, it is easier to 'mix' the putty by rolling in one's hands and blend the few ingredients and the glass tends to set more evenly...I would not encourage using raw linseed oil as it is very slow drying...even if one cleans the glass and wood surfaces well, the raw oil may interfere with finish paint adhesion (especially water based paints)...the blog author is fairly new to window restoration...

when getting set up to glaze, I have a small squirt bottle of BLO handy...the deeper into the bucket you dig, the drier you will find the putty...spread out a good sized ball of putty, squirt BLO, roll and knead until the consistency is proper...
putty can be hearted in a microwave too...please don't invite me over for dinner though!

...jade



Thanks, Jade. I'm sure glad I didn't use RLO! Does adding the BLO actually also speed drying? If so, it seems like it might actually be an unexpected peripheral benefit! I would love for you to send a photo of your rabbet with glazing, before the glass is seated, just to get a sense for how much "bedding" I need to roll out. sometimes I think I'm using too much and other times not enough. My confidence level stinks :-(
Matt


I built a chimney for a comrade old;
I did the service not for hope or hire:
And then I travelled on in winter’s cold,
Yet all the day I glowed before the fire.


-Edwin Markham

heartwood
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Re: Thinning Sarco Type M

Post by heartwood »

mj, i'm sure your confidence level doesn't stink as much as my ability to post photos...I am technically inept and impatient with all things electronic...

I decant my sarco type m into pint and/or quart sizes...I start with nice clean putty for bedding the first sash...I push about 3/16" height of putty onto the rabbet...I set the glass using an oscillating (thank you spell check!) sander....the putty squishes out at the interior and the exterior of the sash but mostly at the interior...using a clean putty knife held flat on the glass up to the edge of the rabbet , I push along to remove excess putty at the exterior....I set the points then flip the sash over and remove the excess putty from the interior...this putty goes into a container marked 'bedding'...since it may pick up dust and debris you don't want to use this for finish tooling as the debris will show up as bumps and who the heck wants that?! why am I telling you all this to answer your simple question?? because you need not be hesitant to use too little bedding because it will not go to waste...when first starting out, everyone uses WAY too much...the most important thing is that there are no voids and the bedding ends up being about a 1/16" thick....

the BLO does not speed up drying (actually, it increases dry time) it just gives you the correct putty consistency which will be reflected in its longevity...what does aid in the time it takes for the putty to skin over is having a fan blow over the glazed sash in a dry environment...the fan offers a 'slow dry' affect rather than a 'quick dry' method like thinner or naptha...

hope that helps....
....jade

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GibsonGM
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Re: Thinning Sarco Type M

Post by GibsonGM »

I thrown my putty on top of my wood stove, on a board ;) Just for a minute or so, then knead it REALLY well. This seems to do wonders for it! Of course, it's the heat of your hand that is usually what's required to get it to the proper consistency. I shy away from adding BLO unless I really have to, as I've found it can make a mess pretty quickly, and increase 'skin' time, but sometimes you really have to, just a little, or you'll be miserable and have to work with putty that 'tears' and drags.

Don't forget to take the sandpaper off the sander when you set your glass, ha ha! I put a nice terry cloth towel on the pane, and use the felt-covered bottom of the sander, like Jade does. Slide the cloth + sander around on the pane til it squishes out enough putty, 1/16" bed. You'll be surprised how well this works! It's fast!

heartwood
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Re: Thinning Sarco Type M

Post by heartwood »

I've worked on triple hung 20 light sash...let me tell you how nice it is to set 60 panes of glass with that sander! I paid $39.99 for my 'no brand' sander specifically for the purpose of setting glass...it's about 5 years old now and shows no sign of slowing down...the sanding pad has a thin veneer of hardened putty that tends to polish the glass while setting it!
and no bloody fingers in the off chance a pane breaks...

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GibsonGM
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Re: Thinning Sarco Type M

Post by GibsonGM »

Weird, but this may be a time to actually RECOMMEND someone use Harbor Freight, LOL!!!

I use an old Craftsman that the pad just WON'T stay stuck down on...the felt constantly comes off when sanding wood, even after being put back on with contact cement. It will stay on for glass, tho. I guess it likes that job more than its old one....got a new wood sander, and use this one SPECIALLY for setting glass... :)

They REALLY do get them well-set, and uniform! Love that trick.

historicalwork
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Re: Thinning Sarco Type M

Post by historicalwork »

May i ask what you guys mean about a sander for setting glass? It sounds like you're not just talking about sanding wood to prep for priming / painting? Is there something more here? It's been a couple years since I restored three of our windows - with, as I recall, a lot of help from jade - and have a few others I may do this year. Every time I go up on the barn and see my "beautiful" steam box, I think about doing more windows....

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GibsonGM
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Re: Thinning Sarco Type M

Post by GibsonGM »

Hi Historical....yes, you can use a "palm sander" to set glass. You put the proper amount of glazing putty in the rabbett per what Jade wrote above. Insert your window glass. Then place a clean cloth on the glass, and run your palm sander back and forth on the glass, corner to corner, etc. (no sandpaper, LOL!). I like using a terry cloth between glass and sander just because.

The vibration of the machine sets the glass into the putty, much faster and easier than doing it by hand. Like, in about 10 seconds. Then you set the points to hold it in place, "trim" what got squeezed out on the inside, and glaze your sash. Try it some time! :)

historicalwork
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Re: Thinning Sarco Type M

Post by historicalwork »

Good to know - thanks!

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