Problem with LMI repair heating blanket

[Dave Richard]

I recently bought the LMI 'bridge' blanket to use with the older LMI timer/temp controller, which I've had for several years. I've used the controller with the fingerboard extension blanket, which has worked well.

The new bridge blanket does not seem to get hot enough to sufficiently soften the glue(but the fingerboard blanket does).  I checked the temperature of each(with a contact thermometer): the fingerboard blanket reaches just over 300deg. F, but the bridge blanket just under 250 deg. F.  I left the bridge blanket on a bridge for 25 plus minutes, and the heater failed to soften the glue sufficiently.

According to tech support at LMI, there is no way to adjust upward the temp setting with my controller, once the slider is on 'max'. 

My question, for others who use these blankets, and this old model controller, is: have you had this problem, and were you able to boost the heat output?  Is there some modification I can make to my controller to boost the output?

I'm also not too happy with the 1"x5" footprint of the bridge blanket.  Is there a source for a blanket that actually matches the shape of a Martin bridge?

[Robbie Collins]

You can probably get these answers by contacting Benchmark:

http://www.benchmarkthermal.com/contactus.html

[Dave Richard]

Robbie, it looks like Benchmark are the makers of the LMI heaters?

Dave

[Mike Kolb]

Have you mentioned this to LMII directly? They may be aware of either a fix or have some other advice they can offer.  

I hear you loud & clear on the shape of the bridge blanket, 1" X 5" doesn't quite do the job.... another 1-1/2" in length would adequately cover the bridge ends. So far, I've not seen anything in that length.

[nathan clark]

Ya, I'm not the biggest fan of the LMI bridge heat blanket myself.  I too have the old temp controller that seems to work fine with my bridge plate blanket.  The bridge blanket does work fine on thinner non-belly bridges but it takes a little longer than a heat lamp and cardboard-aluminum foil shield.  I don't even bother using the blanket on martin bridges anymore because the heat lamp is so much faster with a belly bridge.

My initial reason for buying the bridge blanket was to eliminate the need for all of those heat shields (aluminum foil-clad pieces of cardboard with different bridges cut out from the middle of them).  But these days I only have a few of those and they are all a little oversized and have excess foil that's loosely taped to the cardboard.  I place the shield on the top around the bridge then squish the extra aluminum foil into the gap between the bridge and cardboard.  This works like a charm and I probably won't bother replacing all of those cardboard cut outs that I enthusiastically threw away a few years ago when I bought the blanket and temp control.

The lackluster performance of the bridge blanket is probably the reason that I never bothered to buy blankets for fret fretboard tongues or fretboards.

[David Farmer]

John Hall at Blues creek has 6"x1" heating blankets.

I use silicone foam rubber to get good contact.

No heat shield needed. I can keep heating as I slide the spatula under.

No temptation to finish before the glue cools.

No stress about what's going on under there.

[Kerry Krishna]

David, this is so well done. 

[Robbie Collins]

Nice! What thickness foam rubber are you using, David? Are they permanently attached to the caul?

[David Farmer]

Its 1/8" from a 12"x 12" sheet  I got from MSC some years ago.

This one is glued w/ silicone glue and cut in the Martin footprint but I have some loose scraps for odd bridge shapes.

This thin ply from Home despot will catch fire before it delaminates.

I know this from the time I tried to bend 6 foot eagle wings over my bender for my daughters school project!

Here is one for bridge plates. less exciting than wrestling the roasted Aluminum chunk, but gets the job done.

 

[Steve G]

This might be worth your while

http://www.amazon.com/gp/product/B000I8XDBM

[Dave Richard]

Thanks for all your replies and suggestions. I am returning my unit to LMI, may opt for the 6" Blues Creek as a replacement. Dave Farmer's silicon faced cauls are a great idea.