Repairing sanding belts?

[challenger]

Yesterday I tried some 3m pacing tape. I used one small piece to join the splice and a much longer piece on top. I removed the original adhesive with a small wire brush on a drill and cleaned it up with lacquer thinner then blew it dry. First attempt was a fail. Second try included adding some heat and then clamping. I figured the heat might help the glue penetrate the material. This worked well until the belt was put to metal where, guess what"? The glue heated up and let go. I'm a certified idiot Btw.
What irks me is that nobody can find out what type of glue manufacturers use. According to the research I've done no manufacturer will share this information.
Obviously the makers use a glue that doesn't need 6 days to dry while holding your tongue a certain way. Im sure it's some sort of heat activated adhesive that can withstand the heat that's generates during normal use. I've never had one separate at the seam unless it was old and about to let go like those sitting in my drawer.
On a good note I discovered the Dotco sander I bought for $15.00 sells for over five hundy new. So that's something. I guess?

[Noitoen]

How about a flexible 2 component glue like this:

[JoeLee]

Threads inquiring about repairing sanding belts have come up before. I have a few brand new Sait 4" x 24" belts all brand new that popped at the seam as soon as I hit the trigger on my belt sander.
My fault for keeping them in my up stairs wood shop where temps can reach 110 deg. in the summer. I haven't tried to repair any because at the time I don't believe anyone was successful at it.

Has any one called one of these abrasive belt companies to see is any type of hot taper is available or what can be substituted??

The seam tape on the belts I have look like that heave packing tape with the nylon hair strands in it. It's not very thick and can't be or it will thump as it goes around and hits the platen.

There are some newer adhesives that have come on the market since the last time I saw a thread on this topic. One that comes to mind is that new Flex Paste. Not the tape as it's way too thick.

JL................

[Rich Carlstedt]

...........................................
..What irks me is that nobody can find out what type of glue manufacturers use. According to the research I've done no manufacturer will share this information.
....................................

10 years ago I was given a project which required dissolving the glue used on paper labels applied to plastic film-- Turns out over 200 different adhesives were used and many were proprietary and that meant individual lab testing to determine a solvent for each adhesive ..not an easy task

...........You said, "...But away from the seam/splice joint". Could you elaborate a bit more on that? How far away? And does this mean that you are wetting the paper backing of the sandpaper and letting it wick into the joint? You said "swege", whatever that means in this context. It seems that could be a matter of wicking for two or three or more inches which does not seem to be a practical thing. So, just what does this mean?..........................

I meant squeeze Paul
First I should have said is that you want to clean the back of the belt with a wire wheel to expose raw abrasive belt backing , and maybe scrap the exposed tape with a knife to remove excess glue. The original tape is what ? about 1 inch wide and that means you now have 1/2" of exposed tape along the joint, so i apply the Super glue 1/2 "from the joint on the belt and then lay the tape on it and squeeze the glue upto the joint when the steel bar is clamped. My theory (?) is that too much glue at the joint itself causes the tape to fail as it prohibits flexing. Now when the belt bends round a roller , you may see a slight rise in the belt away from the tape at the joint like1/32 or 1/16 ( a tangent point so to speak) but I have not had a problem at the platten ( which is flat ) with failure or ripping of the belt .

I don't like to wash the belt with any solvents as they may have minute amounts of water in them which can preharden the glue before it grips the belt fibers. The lone exception is Nitro-methane , which dissolves Superglue but that is out of my budget . Also remember to have fresh Superglue and that is takes 24 hours ( Read Loctite Info) to reach full strength.
Just because it is holding the belt together does not mean it is ready for work !
Note, that the steel bar clamping, forces the glue deeper into the Belt backing fibers .

Rich

[challenger]

10 years ago I was given a project which required dissolving the glue used on paper labels applied to plastic film-- Turns out over 200 different adhesives were used and many were proprietary and that meant individual lab testing to determine a solvent for each adhesive ..not an easy task



I meant squeeze Paul
First I should have said is that you want to clean the back of the belt with a wire wheel to expose raw abrasive belt backing , and maybe scrap the exposed tape with a knife to remove excess glue. The original tape is what ? about 1 inch wide and that means you now have 1/2" of exposed tape along the joint, so i apply the Super glue 1/2 "from the joint on the belt and then lay the tape on it and squeeze the glue upto the joint when the steel bar is clamped. My theory (?) is that too much glue at the joint itself causes the tape to fail as it prohibits flexing. Now when the belt bends round a roller , you may see a slight rise in the belt away from the tape at the joint like1/32 or 1/16 ( a tangent point so to speak) but I have not had a problem at the platten ( which is flat ) with failure or ripping of the belt .

I don't like to wash the belt with any solvents as they may have minute amounts of water in them which can preharden the glue before it grips the belt fibers. The lone exception is Nitro-methane , which dissolves Superglue but that is out of my budget . Also remember to have fresh Superglue and that is takes 24 hours ( Read Loctite Info) to reach full strength.
Just because it is holding the belt together does not mean it is ready for work !
Note, that the steel bar clamping, forces the glue deeper into the Belt backing fibers .

Rich

So have you had success in repairing belts?

I still maintain that these belt manufacturers are using an adhesive that doesn't require a long set time or what have you. My most recent Googling shows that polyimide adhesives may be what manufacturers use????
Can you even imagine how difficult it is to find out WTF is used to seam a damn sanding belt!!! This is cazyness!

[JoeLee]

So have you had success in repairing belts?

I still maintain that these belt manufacturers are using an adhesive that doesn't require a long set time or what have you. My most recent Googling shows that polyimide adhesives may be what manufacturers use????
Can you even imagine how difficult it is to find out WTF is used to seam a damn sanding belt!!! This is cazyness!

It must be some proprietary secret.

JL..................

[Rich Carlstedt]

So have you had success in repairing belts?

I still maintain that these belt manufacturers are using an adhesive that doesn't require a long set time or what have you. My most recent Googling shows that polyimide adhesives may be what manufacturers use????
Can you even imagine how difficult it is to find out WTF is used to seam a damn sanding belt!!! This is cazyness!

yes, I have had success ***, but it is really a pain in the butt---time wise.
It would be great to just smear some glue and stick it together and bang, off to the races.
The procedure I outlined works, but if a belt breaks , It really is the next day before you can reuse it , and then sometimes the other side breaks immediately ( remember to mark the side you repair with a marker so you know if your mend worked.
One inch belts are easy, but 6 inch are a PITA for clamping
Rich

**** Cleaned and wire brushed "dry" belt backing , fresh super glue and long term clamping ( 12-24 hr)

PS What I would really be interested in is the new polymer superglues that use UV light and see if they work ?

[livesteam]

I can't speak for end joined and taped belts as I make my own belts from roll stock. I use non water proof cloth roll to make 1" x 42" belts for metalworking. The machine was modified for high belt speed. Makes sparks with steel. I think it's around 3000 fpm. To make a new belt the tape is cut 1.1/2" oversize and the cut is at a 45° angle. One end is soaked in water at the 45° angle and 3/4" depth long enough to allow the abrasive to be scaped off and the cloth is scraped more to thin it as much as possible. When dry the scrapped area is coated with Elmers woodworking glue, mated to the other end and clamped tight overnight. I tried epoxy. Always would come apart when hot from grinding. Wood glue NEVER failed. I use the belts until they are flat wore out. This info may be of use to some belt repairs if there is room for overlapping.
RichD

[JRouche]

I can't speak for end joined and taped belts as I make my own belts from roll stock. I use non water proof cloth roll to make 1" x 42" belts for metalworking. The machine was modified for high belt speed. Makes sparks with steel. I think it's around 3000 fpm. To make a new belt the tape is cut 1.1/2" oversize and the cut is at a 45° angle. One end is soaked in water at the 45° angle and 3/4" depth long enough to allow the abrasive to be scaped off and the cloth is scraped more to thin it as much as possible. When dry the scrapped area is coated with Elmers woodworking glue, mated to the other end and clamped tight overnight. I tried epoxy. Always would come apart when hot from grinding. Wood glue NEVER failed. I use the belts until they are flat wore out. This info may be of use to some belt repairs if there is room for overlapping.
RichD

Excuse me please. I want to hear more of those\s works. Nice. I like the use it where you can thing. .. JR

P.S} "I make my own belts from roll stock."

[challenger]

I can't speak for end joined and taped belts as I make my own belts from roll stock. I use non water proof cloth roll to make 1" x 42" belts for metalworking. The machine was modified for high belt speed. Makes sparks with steel. I think it's around 3000 fpm. To make a new belt the tape is cut 1.1/2" oversize and the cut is at a 45° angle. One end is soaked in water at the 45° angle and 3/4" depth long enough to allow the abrasive to be scaped off and the cloth is scraped more to thin it as much as possible. When dry the scrapped area is coated with Elmers woodworking glue, mated to the other end and clamped tight overnight. I tried epoxy. Always would come apart when hot from grinding. Wood glue NEVER failed. I use the belts until they are flat wore out. This info may be of use to some belt repairs if there is room for overlapping.
RichD

Do you have a picture?

[JoeLee]

Here is a picture of one of my belts that let go.

JL.............

[Bob Engelhardt]

[snip]
To make a new belt the tape is cut 1.1/2" oversize and the cut is at a 45° angle. One end is soaked in water at the 45° angle and 3/4" depth long enough to allow the abrasive to be scaped off and ... [snip]

Like this, but only needs to be cut 1" longer?


The 1-1/2 longer is what confuses me.

[Rich Carlstedt]

I think what RichD is saying is that he "Skived" the belt .. that means overlapping the belt and that he removed the abrasives to make the belt thin at the joint.

Rich

[dbq49er]

My dad was a shoe repairman and glued everything with BARGE cement. Most times he would put two coats of BARGE on the pieces he wanted to join. He would scuff the surfaces to get a tooth on the pieces. He would let the first coat dry to the touch. Reapply with a second coat of BARGE and wait until it gets real tacky. Put the two parts together and clamp for 12 hours. I get the 32oz can on Ebay, I use the red and yellow all purpose cement NOT the blue/black toluene free kind. I also ordered the cement thinner of toluene to keep the glue fresh and thinner. It will thicken after a while when exposed to the air so keep the container closed tight. DO NOT get the glue on the threaded cap threads or you will not be able to open the can. Two coats and clamping is the magic. Good on leather, canvas,wood, rubber, glass, and metal. I put this sh*t on everything. It keeps my work coat usable for almost twenty years now. Like most of you all, I bought sanding belts by the gross and this keeps them lasting for all the work they get. I use 6" 3" and the 1" belts. Best of luck and keep grinding.

[dalee100]

Hi,

What I can tell you about 3M's process from when I worked in their abrasives division a long time ago, is that the adhesive is proprietary and made by them for their own use. Depending on the product being produced, they used either butt joints or skivved joints. They used a special fiberglass tape with the glue to form the join. The tape had to be stored at -30F and had a room temperature life of about 45 minutes before use or it had to be tossed. The seam was pressed with a heated bar between 230F and I think 280F and at 5 to 15 tons of pressure to make and cure the join. Time and temp varied by width and joint type. It generally took between 30 seconds to 1 minute to make the join. And then the belt was left to cure for 24 hours before it could be used.

The materials did age out at around 5 years and those were disposed of.