What should I do if the Oil Painting canvas is easy to loosen?

Due to the quality problem of oil canvas, it is easy to change the tightness after wet water. Generally do not use wet stretching method for oil canvases with large shrinkage after wet water. If you use a finished oil canvas with a base, you need to spray some water evenly on the canvas before stretching, and stretch it to the inner frame after the canvas is soft, so that the base will not be broken.

For picture frames with wooden wedges, the wooden wedges should be driven into the inner corners of the inner frame after the oil canvas is stretched. After the foundation is prepared, lightly tap the wooden wedges to make the canvas taut. If it is a large picture frame with dead corners, the oil canvas becomes loose after being used as the base, which is a headache for the painter. Pure linen cloth woven with thick threads generally does not appear slack, and famous painters mostly use high-quality linen cloth. If you use ordinary linen or cotton-linen blended fabric, first fix the canvas to the frame with thumbtacks, wet the canvas with water, and tighten the canvas again after the canvas is dry. The purpose of using pushpins is to facilitate removal. If the oil canvas loosens a lot after the first wet, you can repeat it again, and finally fix the oil canvas with a gun stapler. Be careful not to remove all the thumbtacks at once, but fix them while pulling up the thumbtacks.
The method of stretching a large picture frame should first fix the four corners, and fix the oil canvas sequentially from the outside to the inside. Or after the four corners are fixed, simply fix the four sides, wet the canvas and fix it carefully after the canvas is dry and loose, so that the canvas will not easily become loose. If the canvas is stretched too tightly for the first time, the wooden frame sometimes becomes uneven. Cotton oil canvases tend to shrink when wet and loosen after drying, so it is better to use simple fixing methods first.
On cloudy days, when the air is humid, oil canvases often loosen. If it is slightly relaxed, it will naturally tighten after the weather is fine, which will not affect the painting. If the slack is severe, it should be tightened a little more, but not too tight, so as not to shrink the Oil Painting canvas and deform the wooden frame after sunny days.