[Stoves] Making bricks

[Kevin Chisholm]

Dear Frank

frank wrote:
> Kevin,
> Are you serious!

Most definitely I was serious. Assuming the adobe brick weigh 144 pounds 
per square foot, the loading per square foot is 1 PSI per foot of wall 
height. From weight alone, the adobe wall would have top be 300 feet 
tall to crush from its own weight.

  "Reducing the Specification would be the quickest
> solution"
> Changing the regs always seems the hardest. : )

If the Owner is reasonable, the consequesnces could be explained to him, 
and he could make a final decision to accept the reduced compression 
strength, OR to accept a job delay while a solution to the strength 
problem was found.

> What we wanted to do was make the bricks as close to the original as 
> possible, using the same parent material and additives. But the darn 
> regs! The building has been up longer than any other in this area so 
> hard to call it a 'failure'. I have not yet been over to look at it, but 
> I think its the same as most others; they last until water gets to the 
> foundation.

OK... so the 240 PSI is not the problem... the problem was wetting of 
the brick. Going to a 300 psi brick will not solve the water problem...
> 
> My experiment using a hole saw at the end of a drill to take out a 
> sample of brick seemed to work well and, based on one sample as of 
> today, original brick is 240 psi. I am getting more to test today and am 
> getting a better hole saw built for testing it.

OK... this could be helpful to show the owner that 300 psi brick might 
not be all that helpful
> 
> I wonder if having a stronger brick with different properties would only 
> add to potential future cracking?  We have the San Andres Fault running 
> under our feet and its modern bricks for chimneys that fail - go figure.

Brick strength does not seem to be the problem. If the Owner wanted to 
make repairs that dealt with the issue at hand, perhaps he would be 
better off to consider finding a way to increase the water resistance of 
his brick?

Best wishes,

Kevin


> Regards
> Frank
> 
> 
> 
> 
> 
> Kevin Chisholm wrote:
> 
>> Dear Frank
>>
>> Presumably, the repairs are necessary because the existing adobe 
>> brickwork failed. What is the strength of the existing brick? Why did 
>> it fail?
>>
>> If the existing bricks failed because of lack of strength, then 
>> chances are that other bricks will fail also. Is there any point in 
>> installing strong brick when future failing of the existing brick 
>> surrounding the repairs is likely? Will 300 psi brick solve the problem?
>>
>> What is the basis for the 300 psi specification? Would the job be 
>> compromised if the specification was changed to 290 PSI, or perhaps 
>> even 275 PSI?
>>
>> Reducing the Specification would be the quickest solution, if that was 
>> an appropriate way to go.
>>
>> Best wishes,
>>
>> Kevin
>>
>> frank wrote:
>>
>>> Stovers, and brick makers
>>> I am trying to make bricks from local clay for repair of an adobe 
>>> house. Must have a compression of 300 lb/sq inch. I am so close but 
>>> the average of readings from five samples is 295.
>>> We do not want to add lime or tar to it unless we need to. (why do 
>>> they add tar?)  I am thinking of straw or perhaps feathers. Also 
>>> wondering about adding sand(?). Any suggestions that would reduce my 
>>> research time would be appreciated.
>>>
>>> The original bricks have a lower compression but the specs call for 
>>> above 300.
>>>
>>> Also; I have been drying them in an oven set at 40 deg. C for four 
>>> days. They are in cardboard tubes 4.5" long and 1.6" dia. This seems 
>>> to work but I was wondering if they will get stronger as time goes 
>>> on(?) and if there is a better temperature to dry them at in lab 
>>> conditions?  They want to start to make them for sun drying soon to 
>>> repair the building in the fall before the rains come. So the lab 
>>> tests must be quick (whats new!).
>>>
>>>
>>>
>>> Thanks
>>> Frank
>>>
>>>
>>>
>>
>>
>>
>>
>